This list of (supposedly 7388, didn't realize there even were that many?) of them can apparently now be registered online replacing the email method in the OP: https://localitymanagement.us/registrar/domain/delegatedzone...

edit -- seems like the server has been "slashdotted" by this thread, I was finally able to get an account created but can't log in. doesn't seem very well coded anyway since I was apparently able to change the password twice using the same activation link lol.

Amazing slow site. If it does manage to find a valid domain, it doesn't show any contact info, nor registration form. Do I need to create an account and log in to see those?