Bet you don’t have UCBerkeley.xxx.edu
A quick WHOIS check says that the TLD "XXX.EDU" is not currently registered. (Wow, I assumed it would be!)
"UCBerkeley.xxx.edu" would just be a subdomain under that. So if you registered "xxx.edu", you could have subdomains for all the great schools in the world!
Go for it!
---------------------------- whois xxx.edu This Registry database contains ONLY .EDU domains. The data in the EDUCAUSE Whois database is provided by EDUCAUSE for information purposes in order to assist in the process of obtaining information about or related to .edu domain registration records. The EDUCAUSE Whois database is authoritative for the .EDU domain. A Web interface for the .EDU EDUCAUSE Whois Server is available at: http://whois.educause.net By submitting a Whois query, you agree that this information will not be used to allow, enable, or otherwise support the transmission of unsolicited commercial advertising or solicitations via e-mail. The use of electronic processes to harvest information from this server is generally prohibited except as reasonably necessary to register or modify .edu domain names. You may use "%" as a wildcard in your search. For further information regarding the use of this WHOIS server, please type: help No Match----------------------------