$ <img src="http://www.catsailor.com/forums/images/graemlins/frown.gif" alt="" />

All joking aside, the reason for ply was that my designs I've been playing around with have been somewhat more traditional (in the loosest sense). Really good 4mm ply taped with carbon is the best material I can afford on that scale. At 13 pounds for a 4x8 section, it's not too much heavier than the alternatives.
If it works, then I'll look at the pricey stuff, and just swap the rig.
I was thinking of heavily canted boards to convert heel to lift, should solve the excessive hull-flying and let it plane easier (semi-foil). Somewhat more traditional hulls would also be less affected by slight heel.
I'd even considered using the longest windsurfing fins I could find for rudders.

Of course, you could just shape two 12' paddleboard blanks, cover with epoxy and carbon, fabricate 2" x 8' carbon crossbars, raid a 12 meter windsurfing sail, add a layer of carbon to the mast, use skegs for rudders and daggers, and be in the water really quick - don't think I haven't considered it <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />