A generic (eg non country-specific) top level domain that is short (on the order of 2 - 3) letters would be ideal. sourceforge.net has sf.net
The two most ideal domains are wp.net and wp.org
whois says that wp.org is owned by telepathy.com, a us based internet focused group that does not seem to be greedy.
A well placed email by a wikipedia official asking for release would be a good thing.
Please keep the list aprised of your activity regarding short domain name search