The video processors would probably run about 1200 and up so yes, returning the tv and getting one that has greyscale and CMS would most likely be cheaper. It doesn't have to be high end tv for those controls, my budget LG 50PW350 which is a 720p plasma tv that went for about 750 (for 50inch) has 20 point greyscale and "CMS" (the CMS doesn't work quite right).
I think Samsung and LG tvs tend to have these controls. The other question is whether you need them or not. Have you checked your tv with a meter? My friend's SONY tv doesn't have CMS but his primaries are very close to perfect and closer than I can get my LG with the CMS...granted his tv cost twice as much as mine for a 46in.
My projector only has basic greyscale controls (only RGB bias controls), a few gamma options, and some brilliant color options. But using just these can get me to 2.2 gamma.
The onkyo txnr809 has isf controls, plus it's a pretty awesome receiver for the price you can get it for. If you need a receiver as well then that might be an option. I've seen refurb 809s for 650. I bought a refurb 709 for 450.