There is nothing special about these transmissions. Rebuilding them isn't any more complicated than any other manual transmission. Look for a good local transmission shop, or buy a service manual, take it apart yourself, and have a machine shop change the bearings for you.
If you farm out the bearing work, the only specialized tool you will need is a dial type torque wrench to check the bearing preload.
Contact Johnny Spiva at Polybushings. He's in your area and may know of a good transmission shop.
http://polybushings.com/