Yup, it's a cool (if old) idea. I'd be up for the build-a-beater comp, if I had the garage space. As it is I'll gladly do a run what ya brung comp... A few concerns about the budget comp:
1. The no cage rule, under this rule, I can build a tube buggy, and throw a thousand dollars worth of engine, tranny, and axles in it. Is this the type of vehicle we want to show up, or should there be a rule that says you have to have a stock frame/tub, or something like that?
2. Hypothetically, let's say I buy a YJ for $1000. I then sell the top, doors, tailgate, stock axles, wheels, tires, etc, etc, etc , for $2000. Can I use that $2000 to build the vehicle? Technically I only spent $1000. This is how I built my Jeep, and I had very little money into it because of that.
3. No spectator fees, no official entry fees, no toilets, no sponsors, no fliers/advertising. Once there is big (or medium) money involved it is going to get out of control quick.