Evolutionary dead end? Allow me to present the GT Tachyon
Designed to ride dirt in the morning. then, swap the tyres, slide the wheel back in the front dropouts, flip the stem down, and go for a road ride in the afternoon.
* 700D wheels (587 bsd). Instead of using other similar wheel sizes (650B has a 584 bsd, 650A has a 590 bsd), GT decided to invent their own size.
* The fork has a sliding dropout so you can alter the mechanical trail for different handling.
* The stem is a Ahead style stem fitted to a double-ended quill and a normal threaded headset. So you can flip the stem.
* Suntour Command shifters came standard. Brifters took their place in history.
More info on Tachyons HERE
(includes catalogue scan)
More photos of mine are HERE.
PS that two wheel drive bike of Oneschnark's is insane! Love it!
White Industries LMDS Front Derailleur adapter/shifter/etc (kinda dreaming on that one...)
Also, any old/weird gear changing systems from 1900-1950ish: cambio Benato, Fiocchi (API), Gambattto, etc etc