I suggest you do a web search for Klingon costumers, contact those you find, and present them with your costuming challenges.
I have come across a number of costumers over the years who do custom work. My current sources follow:
- Trish’s Stitches
and q’IDar’s site
; both come highly recommended.
- The Internet Media Costume Resources List
lists a number of Star Trek-related costume sites, though I do not know how current or comprehensive the list is.
- Shadowdale Creations sells a variety of Klingon clothing and accessories
in standardized sizes, but also does custom work
If you come across anyone who is of help in accommodating costumes to wheelchair use, do come back and post their contact information. This question has come up before. There is definitely an untapped market out there.