I'm looking forward to the paraplegic Olympic sailing and was wondering how they do it. A bit of Googling turned up the Skud 18 class, designed to be sailed by people with all levels of physical ability:
http://en.wikipedia.org/wiki/SKUD_18http://accessclass.org/default.asp?Page=18384&MenuID=Classes/13153/0/
The helmsperson can transfer manually and be steering with tillers, or be in a fixed seat on the centreline using a manual joystick, push/pull rods, or a servo assist joystick with full control of all functions. The forward crew can either be on the centreline, transferring manually, even riding trapeze.
The sides are flared for extreme stability, she is unsinkable and heavily ballasted. Main and jib are 150sq ft, spinnaker 200sq ft and she is exciting for all sailors regardless of their mobility.
The seats can be canted up to 25 degrees with an electric winch, other electric winches can control the tiller and sheets.
It's a great design and it promises to be fun to watch the races.
-Paul