Are you sure that namecheap.com doesnt automagically register the domain and then try to charge you a higher rate?
I know that Network Solutions does that, but I don't think namecheap.com does that. I hit one domain a few times while testing and it was always available.
Apparently people are buying them. Within the last 10 minutes 2 that I was looking at were snagged. :)
That's awesome! I'm going to work on a script that will scrub the array of domains that are already registered. That way, you should always be able to generate an available domain.