Would it be any sort of violation of the letter or the spirit of the Jam if the base rules were all on one page, and maybe advanced supplemental options were available? Or does that look too much like a workaround for an overlong project?
I'm thinking like a 3-class Fighter/Mage/Rogue base, and a half-page Paladin/Assassin expansion for advanced play or something in that vein. A later development to turn a solo/small combat game into military siege engine combat scenarios, maybe.