Ok, I know that you can use Paul's Motolite brakes to run a 700c wheel on a 26" non-disc frame, but they are somewhat cost prohibitive, even at cost, and especially for a winter beater bike. Does anyone have any other suggestions on how to fit 700c's? Perhaps there is another brake set that would do the job much less expensively? I'm close to giving up and going 26", but I'm pretty bent on the idea of a 700c cross bike for winter, without having to buy a new frame.

Tektro V-brakes come up about 1"-1.5" short FYI.

Have you considered ignoring the brake bosses and going with old fashioned calipers? Assuming, of course, the frame will accomodate them.

BMX canti's? I thought of that option for the front of my rock hopper....

I'm not a big U brake fan, not enough stopping power for my tastes. They would most likely work mounted on the fender holes, but like i said not powerful enough.

Ive seen this done, but it was with a fixed gear setup. The used road calipers for the front and nothing in the back. You would be surprised the braking power you can get out of road brakes. The mid 80s diacomp brakes with koolstop salmon pads stop my road bike very very well. I actually like them better than the Vs on my mtb because they have great modulation.