They say there's a wire that secures the weight of the bag off the mounting system so it doesn't sag, yet a couple people talked about that wire straining and stretching visibly over time, and after enough miles it snaps and the bag sags down dramatically. Here's the review. It's by G. Zigler.

"Touring the coast gave me LOTS of time to watch the cable stretch and the mount ("Fixer 3") rotate forward with each bump in the road, until the braided cable eventually broke, one strand at a time. Miles from the next town, I had to use our spare tandem derailleur cable I purchased weeks before in Oregon. Let me emphasize that without the cable your bag WILL eventually "droop" (rotate/pivot) downward - no matter how tight you squeeze the mounting clamps to the handle bars - and your bag will hang pathetically from the front of your bars." -G. Zigler, on Topeak Tour Guide

Hmmm... Interesting. Looking at my pictures, I've had this bag since 2006. In all these years I never felt like the cable was actually doing anything, it was just there in case of emergency (as was told). Sounds like the weight of the bag was pulling on the cable for the person writing that review, but I honestly don't know how they had it mounted.
Right now the zipper is coming apart, I've stitched it for now and the screw in the mount is stripped, so I replaced it with a zip tie. I still feel it's safe enough. I'd absolutely hate if my camera fell and broke, but at the same time it's insured and I'd rather enjoy than worry about it too much.

If you think the Cannondale bag will work, go for it.

Thanks for the info!

UPDATE: I got a pair of 18-48in Rok Shock straps for motorcycles. Not UL, but strong and reliable. I filled my dry sack with all my night gear and spare clothes, mattress, and tent (80% of my stuff) and strapped it to the frame.

Then, I took the slack webbing, threaded it through the four harness points on my camera bag, and tightened it down to the rack on top of the dry sack. Voila!

CONS: I cannot get the camera while riding, and I need to get off the bike to get it out of the bag.

PROS: It's rock solid sturdy. I would use a $200 point-and-shoot while riding but never my DSLR anyways. The bag can easily hold more things, all pockets and straps are accessible. There's 5 separate tie-down points so it won't fall off. Getting the camera out takes seconds, it's in a zipper. Everything weighs about 11lbs.

I've got a Cordura rain cover for a backpack hanging in it's stuff sack off the side, ready to cover everything if it rains. I'm pleased. It's not what I had planned, but it should work just fine.

I will post pictures tonight. The entire getup is the width of the rack, and as high as my seat.

Yay! Success!

Here's my rig! Just needs a frame bag and maybe a top bar bag.

THE SAGA CONTINUES:

After putting 100 miles on the bike with this setup, I'm a little more reserved. It holds on well and I have no fear of the camera falling off, but there is readjustment with some frequency. I think, instead, I'm going to use a neoprene sleeve and a little daypack. It seems to be the simplest solution, and while I'm not crazy about riding in a daypack, it's also 2x as lightweight. It should do the trick.

The daypack I'm using is a Boreas Repack 15, which is very water resistant (siliconized nylon) so it should do the job. I'll have a plastic bag for the camera, of course.

Thanks all for the continuing help and advice.

With all the futzing around that you are doing, you could have just sprung for the Ortlieb. It is waterproof...by which I mean torrential downpour waterproof. It's very, very rugged...mine has several thousand miles on it and the plastic bits are holding up just fine. It will carry an SLR in a suspended bag and always at the ready. And Ortlieb got it's name by making outstanding equipment of very high quality.

Klick fix bar bag mounts And their extender will clear those top mount brake levers,
and the Ortlieb bags will fit on KF mounts too FWIW.

think Ortlieb bag HB Mount has a extension piece, too, but not sure..

I thought that photographers might have something to say about this, and Google found me a thread on dpview that might answer this: How to take a DSLR setup on a cycling tour?

It's a lot of money for something like that. A LOT. I get that it's quality, but I will gladly spend my spare time futzing around, if it means a work-around that costs me less.

THANK YOU for this. It kind of ends the conversation regarding handlebar bags for me:

"This area of the bike is subject to extremely high amplitude/high frequency vibrations and road shocks and is not kind to delicate camera equipment. Hanging a weight off the front of the handlebars amplifies the effect (think road buzz)."

I'm going to play it safe and use a backpack so I don't damage anything. Even if other users rode X amount of miles with no damage, every bike is different and I wouldn't want MY camera to be subject to vibration, especially because I like my PSI on the higher end.

Dpreview is full of wannabe scientists.

Yeah, but it's enough, at least for me. The shred of logic in it makes me not want to risk camera equipment. The sacrifice, in this case, isn't steep.

IMO, if the "road Buzz" is enough to damage the camera, you may need to re-think your bike set up anyway. Is it really any worse on the front of a touring bike than the floor of your car? what if the front end is out of alignment and there is a high frequency "buzz" in the car? or worse yet bouncing around in the trunk. This is the same kind of logic that keeps you at home in the garden taking pictures of flowers while holding the camera with cotton gloves.

The camera will get used more if it is easy to get to. The more you use it, the more likely you are to get shots you want to keep. The easiest place to get to a DSLR is in a front bag that you can reach from the saddle. Everybody will work through the process and finds what works best for them.

For me it is a bag suspended between the bars. The camera protected on all 7 of 8 sides like a roll cage. Wide tires properly inflated makes the "buzz" a non issue. Handling, front loading and all are becoming a non-issue as well with bikes designed appropriately.

I like the idea of the camera bag reverse mounted with hooks. I don't think I have a camera bag that has a good place for the loops, but the idea appears to work well.

I lost my Canon G11 recently and am going to try taking my DSLR on a t-shirt ride with the road bike this Saturday. I have one of these Garneau handlebar bags

and a padded insert to protect my camera. I'll have to temporarily move my computer and take off the light bracket.

Rhode gear used to have a mounting system that worked similar to that, looping around the stem and bars, with a short bungee that wrapped under the head tube to keep it from bouncing. The bag then had a bracket that locked into the tubing mount. I thought the system worked pretty well. wish I still had that bag. Most of the bags I've seen of late use clamps that need to be very tight on the bars to keep the bag from drooping.

I actually think the way the Ortlieb bag attaches dampens the effects of vibrations by allowing some swinging motion.
Everyone has their own preference, but after 36,000km with up to ££££ worth of camera gear in it, I'll happily use Ortlieb again! There's also less chance of it getting damaged if you fall off / crash too (compared to if stored in a pannier or a backpack you are wearing) - and that is far more likely to happen than the cable breaking (for me at least! crashes 3 v cables 1!)

And Bikeforums.net isn't?

I mounted the Garneau bag on my road bike last night. Not really happy with it, but it was still a fair deal for $13 on sale at Nashbar. It has one of those plastic QR brackets that clamps semi-permanently to the handlebars, which I don't like. I want something with a bracket that goes easily on and off as needed, so that my bars are free for my computer and lights the rest of the time. It also sags down a bit because it is all hanging off the bracket at the back and the internal supporting wall is a flexy piece of plastic.

Here's what I was describing earlier, which hooks over the bars & stem in the same manner as what Rollinalong posted earlier.

Rhode gear used to make a bag mount that hooked over the stem in the same manner, but was supported by a thick piece of wood inside the bag and a bungee that went under the head tube. It was very stable. Couldn't find a picture of one, however.

Just about any handlebar bag dampens the vibration. They are suspended and, being a nonrigid box, they don't transmit vibration all that well. A backpack would provide the same vibration isolation but it's not optimal for the same reasons listed above.