The whole idea is to view ourselves live in 3rd person. A camera will be mounted to ourselves looking at us from behind. A video goggle setup will then allow us to only see ourselves in 3rd person.
We will explore how to make a setup like this for relatively cheap. We'll look at other permutations, such as transmitting the data, using the setup in paintball with a marker mounted camera, and so on.
[edit: check out step 10 for the 3rd person view]
Step 1: The Camera's
Some digital cameras or camcorders can do video out as well. That will work, as long as it is live.