Jack:
First, there are some small ship lines like Oceania out there that are no more costly than HAL. Second, if a ship like the 650 pax Oceania Regatta does not fit your requirements, booking your cruises on the smaller (under 2000 pax) ships of HAL, RCI, and the like will help some. Avoid the megaliners. Third, I know many people of both political parties who feel that too little is done to accomodate persons with disabilities in the entire travel process.
Thanks,
Richard