To those who think it's not doable, it is (read Ando's posts)...and it wouldn't require all new TV's with UWB or all that jazz. All that would be needed is a wireless transmitter inside (or plugged into the digital out) of the Revolution deck that sends A/V to . The Revolution doesn't have to render and send different A/V to different TV's, it can just send the same A/V to each wireless TV adaptor. On the adaptor there would be a button that would select which quadrant of a multiplayer splitscreen it would display (player 1, player 2, player 3, etc.) so that each player could have their own private screen for certain games, while other games (like SMBros. that isn't splitscreen) could just hit the button until the full image is displayed. Developers wouldn't have to sacrifice resources or graphics 'cos it'll only be a 480p (non-HD) resolution anyways...their games would automatically work with such a set-up wether splitscreen or not.
Don't be so close-minded about the value of such a feature. LAN gaming is fun and this ONLY makes it better by eliminating the need to drag multiple TV's into one room and buying tons of cables and hooking them altogether. Let's say you're the type to lug your system around to a freind's place, a wireless adaptor hook-up would be fast/easy for travel. Or what if you wanna use your system in a different room...it's more convieniant to unplug the power, carry it with you, plug it in a different outlet near a different TV, hit a buttom and BOOM, you're moved. Or even better, have you Revolution centralized in your home and keep it in one spot and just play on whatever TV (with this wireless adaptor hooked up) in the house is available. Face it, most homes have 1 PC monitor & 2 TV's...some have even more, these are potential LAN goldminds that can't be exploited 'cos of hassles with cables, routers and conveniance.
DavidDayton also suggested (like I have in the past) that one could use the next GameBoy's screen as a screen for the Revolution. Then (also suggested by me before) I heard about people talking about doing so on-the-go as if Revolution were a portable. The Revolution is already as small as a portable DVD player, add a battery and wireless transmit to your new GameBoy screen and play DVD movies, GCN games as well as Revolution games...in portable form!