there is a rebuilt one on Seattle Craigslist (Maple Valley) but it is for an open driveline. He wants 250 and has been trying to sell it for a while.
The transmission is exactly the same between a torque tube and an open driveline. The only difference is the rear bearing retainer, which also makes up the front portion of the u-joint ball area. The bearing retainer can be replaced, thereby converting the transmission to a torque tube.