Well, I have a 27" Sharp TV with S-Video in. I had to short the power button (which means I opened a paperclip, and jammed it into the space between the power button and the powerbutton hole to hold the button down) so that I could turn the tv on or off by supplying power. The S-Video is a certain channel, so it's always there. Basically, my Mame Cab PC is on all the time(on the network). My "power" switch on the cab controls power to the TV, the Speakers, and the Marquee. When I turn it "off", the pc still runs, but no tv, sound or marqueee. This has worked well for me. I did see that Best Buy had a 27" Sansui (?) color tv with S-Video in for like $185.- that's a real deal (I paid $250 at Sams Club for my Sharp). Don't know how the Sansui is for quality or how the s-video works on it, sorry.
Good Luck.