Another option is to go big with a beam across the entire ceiling width and hide the wires within the beam. If you go big, your ceiling will look more like you intended to decorate it that way and you just happened to have a projector or speaker that is close to the beam. I've seen several ceiling molding photos on houzz.com that looks pretty cool.
Any chance of clearing a groove in the popcorn and putting the wirehider in that groove?
I would think a good strong utility knife and a hammer and thin chisel would do the trick rather easily.
Once the wire covering is in the groove, you could always paint it, cover it with popcorn again if you want.