The last idea sounds like one of the old widescreen movie formats called Cinerama that had three synchronized projectors shooting onto a very large curved screen. It was expensive, required lots of setup time, was difficult to keep working correctly, and showed seams where the images overlapped. I've never seen one in person, but I've been told that it was the 50's version of IMAX. Not quite as good as modern IMAX, but darn good for the 50's.
There was also a recent thread that discussed the IMAX foray into digital projection using D-ILA technoloyg. The particular thread in question was from a discussion of bulbs. It turns out that new bulbs exhibit quite a bit of variation and the IMAX theater had to buy a few extra bulbs each time they replaced them so the each projector would match in brightness and color temp. Of course, the IMAX technology is most likely proprietary and way too expensive for anyone shy of Bill Gates to have installed in the home.
There are some other current threads that cover this same idea from a more cost effective sand point. Alan has been active in looking for a video card that will drive two projector with an overlay shared between the two screens. One of the cards he found was based on the Radeon VE so that will be the most cost effective solution for the foreseeable future. This solution does not support HDTV split across multiple projector however. At least not until software HDTV decoding becomes available.
But just to show what can be done, one of the national research labs has a super high res display system built from semi custom components that is used for scientific visualization, but that system uses 12 (I think) projectors and the output is mostly computer simulation data not video.
[This message has been edited by JoeFloyd (edited 06-21-2001).]