I'd assume you would need the manual mechanism , a set of window cranks and two door armrests that dont have electric button setup. Or you could fab up a set of aluminum delete plates and just keep the door lock button in them.
Yes, you can just swap the manual regulators in the doors for the power ones. Just be careful when you drill out the rivets since the power arm is spring loaded. You can use bolts or new rivets to attach the manual regulars.
You will need new manual door panels and manual armrests, along with the manual regulators and window cranks. The power armrests are longer than manual ones and you can not use them with a window crank since the crank will hit the armrest.
Also, if you are lucky, and want to keep power locks, there are some cars with the locks that fit in the black "inserts" on the top of the manual armrests.
I've been meaning to post a how-to thread on this, since i just did it a month or so ago but i don't have internet at my house at the moment so it may take some time. It really is just drilling out 3 rivets and pull the guts out and either riveting or bolting the manual guts in...it's extremely simple.