I am quite sure the I-20 will fit within the B-class box. How much sailarea does it have?

Will it be a slug? Perhaps.. I dont know. But consider that the point in resurrecting the B-class (or a derivative of it) is becouse we want higher performance boats and some room for experiments.
I am quite sure there is a large enough number of I-20's to keep the class healthy and active. Our toughts and ideas should not be viewed as a treath to the current F-20's and I-20's. As others have said here, the I-20 is strong in the US.

Are you considering building an F-18? Great if you do, but consider where you will find the mast and crossbeams. An old T can be donor for a B class rig/beams (might need new aft-beam), and then you just need foils, hulls and new sails to have a competitive B-class. Thats one of the attractions for me (plus that we mostly do distance races and need the speed. We are a beefy team who will not be competitive on a F-18)

Carl: What exactly is it you want? I'll report back when/if I get some feedback.

If someone have connections within Hobie Co., Nacra or AHPC, it would be great if you could ask them what they think about minimum weight and sailarea.