I noticed that problem on my projector too. Good news is I can localize it to certain sources and certain screens. It is bizarre but I don't notice it on actual content I care about. Look on the right side as you go up it pinches in a small amount. This is on a 150" screen.
Source I duplicated it on was my XBMC client on a particular screen. Go to a different screen within same program and same source, it's not there. Weird...
Watch a movie within program or regular TV...fine.
Theater: Monitor Audio Platinum PL200/PL350C, Seaton Submerssive, 150" 3D Elite Screens +more
Living Room: Aperion Grand Verus, Outlaw LFM-1 EX, 70" Sharp Aquos +more
Stage 1 - Enthusiasm, Stage 2 - Realism
Stage 3 - Obsession, Stage 4 - Acceptance...Which stage are you on?