http://www.youtube.com/watch?v=6I1N4hAnH_I&feature=related Wasn't sure whether to put this here or in the TGIF section, personally I think they should have to put at least a 24' foot header on them, just to make it a bit more interesting.
Be fun to play with. The Fs, F2s, and M2s I've run were not that fast. And you are right. Something just doesn't feel right without a header. Although judging by the machines they are converting, I'd say a 20 footer would be sufficient.