I have to agree with everyone else here. You just can't do it unless you want really crappy brakes. Even a cheapy v-brake decently set up can lock the wheels. You won't find that situation in the disc market. Riders weight is much more highly dependant for discs than v's as well so if you are over 160-170 lbs(guesstimate based on my 190 lbs) you will probably want larger than 160mm up front at least.
bb5s or 7's are the way to go.
Has anyone ever tried the hayes mx1s? I never hear anything about them at all. I've had the mx2s and wasn't impressed. The BB7s are better than them but I'd be curious to know what the mx1s are like if anyone has at leat ridden with them.