My rear channel is just a pair of Monoprice in-ceiling speakers. Not ideal, but works well enough for the job at hand.
Working with sheet rock is actually pretty simple, as long as you take some care to do a good job. (Measure twice, cut once, etc...) useful skill for pretty much any home owner to have, imho. There are definitely jobs I'll leave to the pros, but putting in my speakers and pullign the cable was a job I did myself, since all I had to do was make a couple of holes in discrete locations and then patch it later.
The real issue with "wireless" speakers, imho, is that either they're running on batteries (so likely to go dead in the middle of your movie), or else they need to be connected to power, thus making them not so wireless.