I've been seeing these pop up at a number of places, usually branded under the Onguard name:
They usually sell the wheels and seatpost locks for $60, wheels, seat, and for for $75.
They differ from Pitlocks because you get only one key with the Pinhead locks and ordering another one will cost you $18 + shipping and 2-4 weeks. Pitlocks from Urbanbiketech.com sell for pretty much the same price, except you can shell out $119.99 and pick up a set for the brakes in the package. You also get two keys with Pitlocks instead of one.
Anyone use the ones by Onguard and have tales of happiness or woe about these? I'm curious, mainly because I plan to pick up a set of Pitlocks come next paycheck (mainly because the Pitlocks seem better made), but these Pinhead locks are tempting and starting to be sold at a lot of places in Austin.
I just found a third type of locking skewer made by http://www.veratomic.com. They appear to be just "plain" quick release skewers except that you can pull the quick release tab off. I have not found any good or bad information about these anywhere though.