We currently have our system set up on carts.
One small TV
One Video camera
The Tivos will need to be "activated" before they are usable. Basically, take it home and plug it into a phone line, power it up and register, and then youre off and running.
All in all, depending on what you want to spend, you can find old CRT small TVs for relatively inexpensive amounts, or look to see if anyone is upgrading to a new fandangled LCD TV and need to get rid of their old one. Best way to recycle.
It doesn't really matter what type of camera you get, as long as it can do video output to a monitor without recording (which most can). You may need adapters to accomplish this, but most cameras come with the adapters you will need.
You will need to set up the TiVo to "show live TV" once you are all set up. Then, you can program a delay so it is 5 seconds behind (we find about 15 seconds allows for a pass/turn and then the kids can watch while they rechalk or rest).
The things we found the most difficult are actually finding space and time to use it. We have been eagerly watching LCD prices drop waiting for a time when a cheap 20" TV or so drops enough that we can mount one on our wall and make a permanent TiVo spot for a few events. It is a hassle to put it away every day you use it, as well as having power cords running throughout the gym. The more static and permanent you make it, and easier to use, the better. Most kids wont even realize they are watching themselves, but they get an "aha" moment when they see themselves mess up.
I hope that helps!
If you have any other questions, I am happy to help.