I had it weighed because I was trying to sell it on ebay when I first got back it 2 years ago, it was only about 150lbs. You are right about how not common they are. It lists new at Toyota for $3.5k+, I was asking 1k as it is used and has about 6k miles on it, so it's pretty brand new. I even have it in the factory box still. I got 0 bites on it. Its only OEM in a handful of cars, in the USA all you will find it in is the 05+ Tacoma V6, 05-06 Tundra V6, 05+ Cadillac CTS V6, and 2010+ Camaro V6. That's it, since it is a pretty big transmission and how uncommon it is, you won't get very many hot rod guys going after it. So it's just been sitting in its box under a tarp in my backyard since late 2006/early 2007. I have no use for it and just want to get it off of my hands to someone who does, for a small price of course.
EDIT: I attached some pictures of it that I have.