3D tv technology to show separate shows instead of 3D?

This general idea has been thought up before. One of the problems with your suggested implementation is that it would only work well for polarized 3D TVs. The vast majority of 3D TVs on the market right now are designed for electronic shutter-glasses. These glasses would need to simultaneously shut both left and right eye lenses several times each second and this could become noticeable, distracting and potentially very irritating to the viewer.

As the other responder mentioned, you would lose half the resolution for each view in a polarized system. You do not however have to do it line-by-line, you can instead use a checkerboard pattern that makes the picture seem more continuous rather than skipping each line of pixels entirely. It's not actually that bad when you consider that half-resolution 1080p video still contains more pixel information than a 720p video, meaning you are still getting HD video in each independent view.

Other manufacturers have suggested a dual-view LCD implementation where you see a completely different video depending on the angle of view. Some companies have already proposed using the technology in automotive applications (e.g. Driver sees GPS, passenger sees movie). This dual-display technology does not require 3D glasses, and it is a simpler form of the same kind of technology used to produce auto-stereoscopic displays (true 3D TVs that do not require glasses).

Actually that is a great idea. I hadn't thought of that. Each person watching a show in 2d, but you would have one set of glasses with both set of lenses letting in all the even numbered horizontal lines and then the other set of glasses would only let in the odd numbered horizontal lines. Nice idea.

Yes SONY has patented this technology but has not implemented any use of it.

I've read about this on Joystiq.com and they have mentioned SONY may use it with multiplayer games.