Mike you are right, it doesn't have to be an all out F20 arms race, you could open it up to just sails, lines and blocks, keeping the platform and mast -standard- or you could open it up to a new mast too, if you can find a better deal somewhere else.

OR, you could include all the Hobie 20's with spin, the N 6.0's, Mystere's, etc., with spins, just agree on the box rules, that is basically how the F16 class got going, and tightened up the rules as it grew.

I'm sure you could run a good alum. wing mast on the I20 and not be too disadvantaged if you got some good sails built for it.