Cinelli Bivalent hubs:
It seems to me that you need three hubs (and wheels) to use the system, plus a pit or follow-car. Or are you supposed to carry the spare wheel on your back? :)
Maybe the system didn't catch on because, if you have a pit or follow-car anyhow, you might just as well put two wheels (front and rear) in there. (Or better: four!)
Of course, the miscommunication that sometimes occurred even with the pros, where the support person comes running with a rear wheel despite the front one being flat, won't occur with Bivalents.
Or am I missing something about their use? Of course, the fact that they didn't catch on in a big way makes them all the more collectible now.
As far as spoke hole counts: In a pinch, you ride whatever you can find. Due to various circumstances, I rode the 1999 Paris-Brest-Paris on a 36-hole front and 32-hole rear wheel. I'd save the 32-hole wheel for the spare: less spokes make it easier to extricate from the car, where wheels often tangle into a terrible mess with quick releases hooking up on spokes. :)
Finally, this is not meant to detract from the hubs, which are beautiful, an interesting concept, etc.
Jan Heine, Seattle