I was wondering if a frame from any s10's or a 4dr would be the same.. I have a 2dr 4x4 blazer and want to swap frames to a 2x4 frame. Can I use a s10 frame or a 4dr frame? Or does it have to be a 2dr 2x4 frame?

You would definitely have to use a 2dr frame and it has to be from a non-ZR2 (yes they were offered in 2wd as well in the later years [&o]).

That is a whole lot of cost just to switch your truck from 4wd to 2wd...

you could take a 2wd pickup frame and use the front clip and have that grafted onto your blazer frame otherwise you will need a 2wd blazer frame

What about just taking the 4wd components out and swapping in a 2wd trans and driveshaft?
It would be cheaper and easier in the long run.

the suspensions are very different and if you remove the front half shafts the hubs come apart

If you leave the outboard stub, you will be fine