Thats a shame. I think years ago someone told me that the Israeli Gaboon (okoume) was the stuff that you should try to a hold of.

I bought some sheets 2500mm x 1200mm (a little longer than standard) interstate, and the quality in some respects was questionable, but I didn't have too many problems. I'm pretty sure it was from China, can't quite remember, but China rings a bell.

I don't think you can build these types of boats, with the stresses of building and sailing, with anything but a good Marine plywood, I think it will end in tears.

Regards