There is also the divorced option (no not from your wife - guys like us don't get off that easy and we certainly don't get a cool transmission of our choice for doing so!
). Dodge 205 and an NV 2wd unit that was considerably cheaper than a 4wd unit when I got mine. Support for the 205 can come from the donor truck.
2wd units don't seem to have the 5th gear nut backing off thing going on either.
Think I have 200 in the t case. 800 + the rebuild in the 4500. 350 - 400 in the AA adapter BH. Lots of making things work.
FWIW, try to pull one out of a truck that drives (so you know it works) instead of from a guy in a full leg cast that drives down from Redding in his K5 to deliver.
I think the 2wd units may be a little more available still.
It was a tedious install but with a little ingenuity and determination, wasn't too bad on the pocketbook. Don't spill the gear oil because that's the stuff that is expensive!
The AA Adapter is pricey. Nuff said there. Hydro clutch was an easy decision and works really well. If you get the heavy duty "tall" pressure plate (like a Valeo or Hays) you will have to do a little grinding to the inside of the bell housing. Not much (maybe and 1/8" about 10" long) but worth mentioning. Run a Centerforce clutch and you'll have no issues but will pay more $$$.
I ditched a poor shifting, slipping, rode hard and put away wet TH400 for the NV and do not regret it for a second. It has OD which the 400 didn't have and it shifts like a Porsche compared to the 465 that I had in the '64. It did great behind a 396 and is doing fine with the 454 now.
IIRC, the later LS style has an even more street friendly 1st gear and full synchro reverse which is kinda cool.
I regularly haul well beyond what I'd feel comfortable doing with a 700r4. If I had to go auto, Id have to bite the bullet for a 4L80.