Cyclocross - Choices: fun commuter/trail/cross bike: SS 29'r or SS cross?

I know its somewhat loaded being in the cross forum but I ahve been thinking of a second bike for commuting, fire-roads/trail and cross races just for kicks.
I'm thinking single speed.

I have a geared cross bike I ride/race/commute etc. I also have a road bike which I'll leave as is (but only sees weekend use). I have a full suspension 26" MTB that gets no use now so I'd like to use what I can from that, get rid of it and get something that I can have fun with. I just don't care for the MTB.

So what might be a better option?
SS 29r? Ride trails, could still commute on it and even hit a SS cross race.
SS Cross bike? Same handling, parts compatibility, right for cross but maybe lighter than a real trail bike.

Still on a budget

Probably depends on what type of terrain you want to be able to cover offroad, and how much road riding you plan to do on it.

What kind of trails do you want to hit, and how often?

Trails tend to be single track, sandy, occasionally rocky, XC type stuff. I'm not bombing down hills and doing jumps or anything. I've been wanting to get more time on the trails and I plan to do that this spring.
My Trek Fuel is just old, worn and not set up right for me, needs better fork, and parts for a FS bike are just too expensive for me. I was considering a 26r MTB frame to swapp everything over to, but then I saw a bunch of 29rs racing cross this weekend and thought that might be an alternative.

I'd just buy the bike I liked and not get caught up on names. The dividing line between crosser and 29er is very confused - some crossers definitely have the clearance to be called either at the whims of marketing. A more interesting question (seriously!) is what handlebars were you thinking of putting on the bike. Singlespeeds really benefit from wider bars, but you sound like you'll want drops. So - Bell Laps/Moto Aces? Woodchippers?

The other thing that I'd say from having ridden singlespeed offroad: some more space for "the guys" from a sloping top tube is nice, although perhaps not essential depending on the trails you ride. You'll definitely be more likely to come to an unplanned stop than an ungeared bike on "interesting" terrain. For the same reason, BMX pin pedals are nice for anything short of racing, but then I'm an enthusiast for these anyway.

Sounds like you want a monster cross. The Fisticuffs would fit your needs well.

Good point about the bars and the sloping top tube.
I suppose I could use my riser bars from my MTB, this way I'd end up with two "similar but different bikes". I agree that the lines are a bit blurred depending on how you outfit them. Then again, I could also go back to some other drop bars if I don't care for the risers.

I bought a Motobecane Fantom Cross Uno (steel SS) to ride on trails and fire-roads that I had experience on with my 26" hardtail MTB. I don't race, but am interested.

I found out that I needed a lower gear ratio to handle some of the hills and the bumpy terrain I like to ride on so I switched out the 16T freewheel and got a 20T. Right now I've got the stock 38T chainring with the 20T freewheel and it's just about right, I could use a slightly lower gear ratio but I'd be seriously slow on the pavement so I'll probably keep it as is.

As far as what you're looking at they're very similar concepts but your main considerations are handlebars, frame geometry, and tire clearance. Handlebars and frame geometry have already been talked about but tire clearance is a big one and your only form of suspension.

I have a 38c on my front and 32c as a rear, I like the big front tire to cushion some of the bumps and just last week I bought a cane creek thudbuster suspension seatpost to ease my body.

Upgrades that I want include more shallow drop bars like the woodchippers and perhaps a new fork with disk brake mounts; the stock caliper brakes are nothing like my MTB hydraulic disk brakes and I really miss the stopping power. I also might try to squeeze in a 42c front tire which motobecane clames will fit in my frame.

Do you want a heavier bike with more cushion, or a lighter bike with more get-up-and-go? To me that's basically what your dilemma is and you need to consider the terrain you want to ride. I find the horse-beaten paths around here can be alittle too rough for my liking but the small rock/dirt/gravel roads with moderate and some steep slopes are just right.

Been looking at SS specific frames and am considering a few options - the Fantom Uno with canti brakes
Also, the Jury frame from BD I can use centerpulls on that still fits wide tires. Chrome is just so tantalizing and it may make a fun fat tire commuter.

How heavy are these frames being regular 4130? A regular aluminum frame with an SS adaptor should end up lighter than those and only loses the ability to go fixed for a change of pace.

The Uno is heavy but a solid riding off road machine. I had one for a few months and rode it a ton but never raced it. An alu frame would be much lighter. Also, the uno frame is made for track wheels that are spaced to 120mm. Annoying the I couldn't fit standard road wheels on it.

That's what I'm thinking. I'd rather have several wheelsets and use the cog and spacers for them when I want to run SS. I looked at the SE stout and the thing is 29 lb so I don't see what it gets me over the 30lb MTB I commuted on in the past.

Any real downsides to running a singleator vs dedicated single setup? I've got all sorts of spacers and cogs from shimano cassettes I've taken apart in the past.

I've done the singleator thing without issue for street, MTB and cross. Just make sure your chainline is good and make the chain as short as possible.

Voodoo makes a monstercross bike called the Nakisi, It might be what you are looking for, although it's a 26" bike at the moment and I think available only as a frameset.

I really want a 29r or even another cross bike but it looks to be best for my budget to get a 26r frame and build it with the wheels and parts from my FS bike. I'm even thinking it may be best used as a winter commuter as well.

I've looked at 69r builds though and am wondering about their feel and handling. That'd be an easier build to do and could be swapped with just a fork change. Could use cobbled together parts as well.

What about a Surly Crosscheck? Pretty reasonable in price, can fit tires up to a 45 width and has horizontal dropouts so it will work as a singlespeed. I've been eyeing one myself for this exact same purpose, though for me it will be my main bike.

I'm trying to use what I have now which is a full suspension MTB and jsut swap to a different frame. I'd like to keep it low budget, $100 to $150 to do the whole thing. Adding frame and wheelset is what's hurting me. I have all the 26" wheels and components, may need to stick with 26".

I've got a nice cross bike right now and I can't afford a new $400 frame. If I sold a bike or two maybe I'd have that money.

I've got a nice cross bike right now and I can't afford a new $400 frame. If I sold a bike or two maybe I'd have that money.

If you had $450 and the single speed requirement you should consider the Misfit Dissent (http://www.psyclestore.com/products.php?product=diSSent-AL-Singlespeed-29er-Frame).