We have done some really crazy things in tough retrofits, using a single cat-5 to carry data in two pairs, a composite signal for a camera in one pair and IR in the last pair. Several other things worked. Even coaxial over twisted pair. 10/100 network over a telephone cat-3 cable.
Speakers using cat-5, telephone using coax. All you can imagine.
Trust me, i've made several customers happy by improvising in situations where there was no other way around.

I prefer a wired workaround over any wireless or "over powerline" solution.