There are already adaptors for regular computer monitors to allow them to
become touch screens. Last time I used one, they were OK, nothing great.
The idea is a pressure sensitive base, more or less, attached to a serial
port or other dedicated controller card port.(not a joystick or game
controller port).

As far as for TV's, well, I'm sure the technology could be adapted, but
why? I mean, there are a TON of computer monitors, and the adaptors for
those aren't a "one size fits all" sort of thing. With TV's ranging
anywhere from 2.5" up to a whopping 100"+, that's a big range. Granted, I
doubt we'll see much gaming from anything under a 13" TV, but still, one
never knows. Also, like with TV's, computer monitors aren't just all
CRT's. There are far more TV's than variety of computer monitors. Plus,
with TV's that use a projection system, this would be totally useless
unless using some sort of key-color controlled pointer device. By
projection, I don't mean rear projection units.

Sure, a PDA-type controller with touch sensitivity might be great, but
since that's going to show the entire screen anyways, why use the TV?
Otherwise, your touches will be guesswork and sloppy. Practice will
improve this a little but. Also, doing this via wireless is rather high
bandwidth, albeit you can do full NTSC broadcast at 384K, which is far
below even lowly 802.11b's 11Mbit capabilities. But 802.11(x) uses
protocols to correct errors, where as doing a broadcast of a program is
clear channel and doesn't correct bits of stuff lost along the way.

I think the best solution would be a "gamer's touch screen", which would
be at least a 15 or 17" flat panel LCD display in 16:9 aspect ratio and
RF, composite, S-Video and component inputs. Hell, let's cram RGB and
SCART in there for a few bucks more. It has a special output that goes
into a module that attaches to your gaming system via USB, Firewire or a
proprietary module or device. Have it output whatever video signal it can
take IN and pass it though as another add-on option to the touch screen
unit so it can also connect to the big screen.

I'd say this would run around $500 or so. Oh wait, I'll bet you'll want a
TV tuner in there and multiple component, S-video and component inputs as
well as audio for those as well, including digital audio via copper and
fiber. Tack some more money on and it could happen. Say, another $150.

You know what would be even better?

pushing buttons