As I tested earlier this evening, the bell housing on the back of a 22re 5spd (w56) will bolt directly up to the bell housing of my 3RZ (w59). So, yes, you can put a w59 behind your 2.7l 3RZ.
But this setup is weaker than the w59.
I am looking at the 27-4gt adapter so I can stick with my w59, and then step up to duel cases and such down the road. But I'm still confused.
Why bother swapping thirds when you can swap the entire axle housing with thirds and axles in it. The Taco and post 85 rear axle is the same width, same axle shaft, and same brake drum/shoes.