This came across my email today from Universal Cycles in Oregon. They're selling a really practical wheelset, if only there were a bike to put it on. The front wheel has a 6 volt, 3 Watt dynamo hub to run your headlight, and the rear wheel has an 8 speed internally geared hub. Perfect. Only, the rear wheel has hub spacing of 135 mm (mountain bike size) and the rims are 700c (roadbike / 29er mountain bike size). The rims fit tires from 25-37 mm (touring size). So, they won't fit any road bikes, and won't fit a 29er mountain tire. They might, might fit some touring / comfort bikes with 135mm spacing or a rare cyclocross bike with 132.5mm spacing. You could also throw them onto a 29er frame for use as a pretty bomber commuter bike (ala Salsa Fargo), as long as you run CX tires. In conclusion, they're probably on sale because you probably can't use them. But man, they'd be sweet.
photo from http://www.universalcycles.com/