Awesome post Marc! I haven't done free sites in a quite a while now, but I never was one for creating mirror sites. The time it takes to make them different enough to not get slapped with the Google duplicate content penalty seemed like just about enough time to make a whole new free site.
My sites would only get submitted to 12 or 15 LLs each, but I could rotate the smaller LLs each time so my sites didn't have the EXACT same pattern. I always submitted to the big guys, but there would be 8 - 10 recips to smaller sites that changed with each submission.
I'm still getting sales off those old sites, so I guess I was on the right track!
Biggest thing I learned? Don't give up too soon!