I'm a musician running an iMac and I want to make some videos of my music showing all the different instruments playing at once, with picture-in-picture, like this:

YouTube - Stairway to heaven improv solo guitar,bass,drums cover

I'm not great with video editing, all I've really used is iMovie.

I've done picture in picture with iMovie, but iMovie 09 only lets you do one PiP at a time, and the only way to divide the screen into 4 or 5 shots is to do one PiP, export the file, then do the next, and repeat. This takes forever and loses a lot video quality I find.

Anyway, I want to know what good video editing software is out there for Mac that lets you easily do multiple pictures in picture? I don't want to pay a lot for anything, so something that's cheap or even freeware would be best, although I doubt there are any freeware video editors that have this feature.