I love the mast, sail, and the whole package of being able to sail, paddle and peddle.
One thing I'd change is the weight - it's a heavy beast.
I've love a marriage between something like this: http://smalltrimarans.com/blog/?p=4994
and an AI/TI.
Hull weight of 38kg vs 56kg for the TI (but what that includes for both sides isn't clear - beams? seats?).
OTOH, the spider only has a 160kg crew weight, which isn't nearly enough for a TI - presumably BWL is far smaller.
How smart is the mast storage *in* the hull?!
So I'd love an expedition version, but don't add to the weight (and preferably take it off using some new, space-age (=I don't have a clue how) materials).
Oh, and submersible to 10ft with bow plane controls for the perfect snorkelling companion
Damn, I just noticed that the Spider is closer to the size of the AI (weight, length, etc). Still, maybe Hobie can do magic...