I think your biggest challenge is finding one that is not a cassette hub body that is reasonably priced. The Neuvation's you have listed have a casette body. The Mavic's may be one of your few options in a prebuilt.
If you are looking to go single speed, you can use spacers on some casette body wheels, but they are all spaced for 130mm dropouts and the Langster has 120 dropouts. This means you will probably have to redish which may not be possible on some of the wheels, mainly because the spokes are propriatary. HED3 and some old Specialized Tri-spokes come in a track format. As do Aerospokes so if you are going fixed keep a sharp eye on fleabay.
If you intend on singlespeed, take note you will likely not be able to use a freewheel style hub in an old Specialized Tri-spoke unless you don't mind a fairly screwed up chainline since the hub is spaced for a 126mm freewheel spacing.
Good luck. I think the best option really is to build up a set of wheels with the hub/rim/spokes of your choice. You can build a really light wheel (ligher in fact than many of the sub $1000 wheelsets) if you just choose your parts carefully.
Last edited by Hirohsima; 06-27-07 at 11:07 PM.