One implementation of a sidestick that is quite simple is
shown in some
pictures at:

http://www.melmoth2.com/texts/Pictures.htm

Scroll down past the engine, etc, til you get to the
sidestick pictures.
Basically it's two longitudinal tubes running along the
sidewall, one
inside the other; the inner one does pitch, the outer one
roll.

Peter Garrison

I don't know what the Seawind comes with but I would be cautious
about reducing the amount of leverage you have.  A six inch side
stick is one thing on a cruiser like the Cirrus which is flown on
autopilot most of the time anyway, but in an amphibian there are
situations(rough water) when you need more control force than you
may be able to supply with your forearm.   Dan Stanzione