I'd start off by showing some of our multi-year-old vs. comp games we played. As you'll see (when I finally get around to poking around our old replays) the best one of us is about a 60 APM newbie, and it only scales down from there. With the RWA plugins being released, we could also commentate on just how bad we are, and try to give some insight into the mind of a just starting player.
Nowadays the best one of us is still only a 120-150 APM player, but we've all progessed quite a bit. We are still growing, and none of us have stopped becoming better and better, even though there's only one of us that won't dodge constantly when someone else challenges them.
If anyone has any suggestions, feel free to post them. I'd like to get some feedback on the idea as a whole and see if there's anything people would like me to add. I know watching replays of 4 n00bs fight 4 comps doesn't sound interesting, but I thought it would be fun to see how a couple players advance over the course of many games and learn new builds and such.