It's one thing to design a nice airplane.... but it's flying charistics might not be as nice as airplane looks.... seaplanes take lots maintence to fight corsion etc.
plus engine not as easy to work on due to its location
as for Deaf pilots Assc. they have more than 5 to 8 deaf pilots....think in USA there are about 80 deaf pilots but half those have died or no longer fly (age etc) in Europe and other countries they don't allow deaf to fly anything other than "ultra lights" he in USA the FAA allows deaf to fly what every they want (singles / twins etc they even allow you to have a Instrument rating now with restrictions (must have hearing person on aircraft) but new technology like heads up display "highway in sky" & data link might change all that.
the deaf pilots assc is having their annual fly in June 16th to 21 in Cornoa Calif
www.deaf pilots.com click on fly in. link
I was flying a new 2007 Cessna skyhawk today with Garman GPS its nice