I've found that more and more sites are wise to spamgourmet. If you try to enter a spamgourmet address, your request for whatever will be denied.
Can spamgourmet's IP address be used, i.e.:
something.3.jcllings@216.218.230.148
What about generateing domain names dynamically using a free domain name service and a password generator? Each user could then be assigned thier own domain without the word "spamgourmet" in it, spilling the beans.