[quote name='UncleBob']It *IS* possible, I'm just not sure how.
You know how at some concerts and such, you'll see one image displayed on several TVs that are mounted together to form one huge picture?
I read an article a long time ago about how someone did using whatever the device was that did this, four TVs and a Nintendo 64 (I said it was awhile ago!). They used it to play Mario Kart and GoldenEye. The device cut the image being output by the N64 into quarters, which lined up with what the N64 divided the screen into for 4-player games.
*edit* A google search for 'Mario Kart Nintendo 64 split screen "4 TVs"' gave me this!
http://kontek.net/davidwonn/4tvs.html[/QUOTE]
That is a low end form of video wall or a 'dumb wall' in the business.
http://9xmedia.com/Pages-products/2000 - Xwall.html
For a dumb wall the image is scaled up and sections of it sent to different monitors. A smart wall can switch on the fly to having independent images on each display.
This sort of stuff isn't cheap but it is possible to build your own. If you have a PC with two video card and a video in, you just need smart drivers for the cards. Still, not a trivial expenditure for the desired result.
For games supporting LAN play, getting additional Wiis or just requiring people to bring their own makes more sense. Now that LCD TVs are dropping to reasonable prices the effort to gather several displays in one place is reducd.