The Hard Core has horizontal drop outs, but you still use the pulley thing. Really necessary?
I am personally not a strong believer in the ss and/or fixie concept, in particular as I see my buddys have more hassle with theirs than I with my gears.
Yes, I find that no matter how hard i crank on the QR, the axle still slips in the dropouts and when I get pumping on a climb, the chain will pop off, I'll hit the ground, and wonder what happened till I look more closely. Plus it adds a little bling AND a bit of resistance
Honestly, I can't say that hes every discussed that... That'd sure be an interesting concept...