Okay, here's what I did:
I didn't want to hack a new TV either, but I wanted a simple external "on/off" switch. The PC is on the home network, so I leave that on, but the Marquee light, the speaker amp, and the TV are on a separate power strip that I wired to an external light switch on the back of the cab. When off all is quiet and dark, but with the flip of the switch on the back, the game is instantly on and ready to play. FOR THE TV: like I said, I didn't want to hack the tv, but I found out that I could "short" the TV power button by pressing it in and inserting a thin piece of wire(paper clip) along side of it to hold the button in. It works great, you can now power it on or off via the power plug, the only issue is that this keeps the remote from working(on my model tv). Not a problem for me since I never have plans to change channels in the cab, but it might be an issue for you. This method works great for me and nothing is permanent. I can take the tv out, pull out the wire and it works fine again. Hope this helps......