Consider getting someone to make and add pedal extensions for you. Haven't seen them recently, but I know that it is none for some handicapped. For the original question, get someone to look under the chassis and floor, It might be possible to move the chair mount if there is nothing in the way under the floor.
Noel and Betty Johnson (and Harry)2005 GulfStream Ultra Supreme, 1 Old grouch, 1 wonderful wife, and two silly poodles.