Something I've been toying with lately is running barefoot on pavement. Tonight, I just did a couple of laps at the track in the Vibrams, and then headed for home. I decided to run back barefoot on the pavement. For whatever reason, this doesn't feel painful to me at all. It only took about 5 minutes, and of course, I got a few strange looks along the way.
I actually think I run with better efficiency barefoot on pavement than any other style. Maybe the combination forces more efficiency. I have no desire to run barefoot on pavement just to put on a show, but if it helps me develop then I'll do more of it. Of course, this won't be feasible in the wintertime, so it's a seasonal tool at best.