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.