Out of about 10 of these I checked, 9 were already taken.
I was going to grab eurocentrist.com, but all the cool ones on the top 500 list are actually taken. Even buckminsterfullerene.net. Yeesh.
Yep, almost all of these were all registered, some as early as March.
I checked a few that looked too good to be true and in every case the registrar was godaddy. I'm guessing that they probably block scripts that run mass queries against their system, or maybe they return results in a way that made the script choke.