I am currently in the process of rebuilding a 4l60e which will go into a 4x4 go-kart. I am now in need of a transfer case that will bolt up. Are there any manually shifted (not dash button) transfer cases that will easily bolt up to a 4l60e without an adapter? If not how easy would it be do electronically control an electronic transfer case?
I realize this answer isn't as complete as you want, but hopefully it can point you in the right direction.
So it appears this transmission was used in most (if not all) Chevy and GM trucks from 92 on. Most (if not all) of those trucks were available with 4wd.
I have a 97 suburban with 4wd. It does have the dash button shift, but I've heard it was available with the floor shift. Look around at mid 90s Chevy trucks for part numbers.
Alternately, in looking at aftermarket 4wd stuff, I have seen manual engagement buttons. Look at "actuator upgrades"