With respect, is that all theory and opinion, or based on actually seeing a bicycles of that design fail? I'm familiar with the concepts about torque that you guys are expressing, but I've also put many thousand miles on my daily commuter/touring bike, which is equipped with disc brakes on track ends- using QR levers even- without incident. Its a Cotic Roadrat- http://i56.tinypic.com/vyqkid.jpg.

The bike I'm trying to have modified is a Bianchi BASS- the BASS was an early '90s singlespeed design- after about 2002, Bianchi updated them all to disc brakes (on the DISS, GUSS, WUSS, SISS, etc., and some cyclocross bikes such as the Roger). I'd love to have one of those models, but finding one at a reasonable price, in my size, not beat to hell, and (as a low priority) in a color that I like has been difficult (I've even engaged in- and lost- a bidding war on some guy's lawn when two of us answered his craigslist ad at the same time.)

Some others, for reference:
http://www.cotic.co.uk/product/roadrat
http://surlybikes.com/frames/1x1_frame/
http://surlybikes.com/frames/karate_monkey_frame/
http://www.on-one.co.uk/i/q/FROO26IN...-frame-2nd-gen
The Bianchi bikes are probably all on Bikepedia- there was one model per year for about ten years starting around '97.

Brakes on a racing motorcycle need to stop a ~500 pound object (with a 200HP motor) that's moving 200mph. My brakes need to stop a ~200-pound object (with a 1/4HP motor) moving 20 mph (on a good day). I don't know how many RPM a motorcycle wheel is spinning at at 200mph or how much one weighs, but I'm assuming its energy is a distant multiple of the the forces a bicycle wheel puts on its brake caliper.

Anyway, I'm not arguing the point; I'm simply surprised by the brief, dogmatic replies.