These guys have been spoken about before on the forums, as they offer a decent final drive ratio as an option when refurbing a manual gearbox.
You can get refurbs from under US $2000 including the 3.73 final drive option - this includes shot peening, new bearings, improved oil ways, ect ect.
I have one issue though, they don't seem to answer emails! If anyone knows a gearbox specialist that could potentially offer me a similar service at a similar cost, I'd be interested.
More info on the TRE stuff here:
http://www.teamrip.com/TRE_EVOLUTION..._SERVICES.html