The plug only has to be behind the set, not exactly in the middle.
Unless its a truly small panel there is a lot of leeway.

For instance I'm looking at a 50" plasma that is 30" tall.
So a plug at 50" would be hidden:
If the set was 22" below an 8' ceiling.
If the set was 26" above the floor.
(Assumes plug center is six inches above or below tv's edge.)