I spoke with a member on Facebook about this before nothing really came from it.
I have few special tools to rebuild them at home. I rebuilt mine, but it will be a long time before it will see service to prove the work. I also rebuilt the pump itself, but there isn't a lot of faith there just in parts alone. I've read a lot of complaints about the pumps after rebuild.
I'll extend the same deal to you varzaman. I'll rebuild your gearbox for you at no labor charge. Just cover shipping, parts, and paint if you would like it repainted.
Rebuilding them yourself isn't actually all that bad! Just takes time and care. The write-up that is available is helpful but it is far from a step-by-step, you truly need to read the manual to do the job properly.
The idea is to give us another option for this service, and I'd be happy to help.