yes your vet will definately be able to put you on the right track to find one, or contact your nearest vet university and ask them. also i dont know much about this but you seeing as you are in a big city area then what about animal acupuncture (some vets are trained in it) and/or physiotherapy ?????
also if he is now to get some excercise that will actually help start to build up the muscle, cage rest is a double edged sword, very necessary sometimes but the limbs being immobile doesnt help and you get muscle wastage.
good luck but if the vet says it is stable then i think there will be improvements as he builds muscle, you could ask your vet about "anabolic steriods" ie nandoral this would help build muscle.
also just for interest and i dont know if it applies to felines but i watched a vets hospital thingy on tv a few months back and there was a horse with leg soft tissue injury, they if i remember correctly took bone marrow samples, sent it to a lab who separated out the stem cells, the stem cells were injected into the point of tissue damage and in a few weeks they obviously started growing as the tendon tissue (coz stem cells grow as the tissue they are surrounded by ie if in bone it will turn into bone cells, if in muscle will turn into muscle cells) thus healing faster and better than it would have so the horse could compete again
probably useless info for you but i think it was very interesting and your dillon might have been a canditate (aswell as the ops he needed) when they start doing that type of thing in cats and dogs.