Here is what I received from Shell on Jan 5th. I put in the inquiry almost 2 months ago.
"Dear Biker,
Thank you very much for your email. It's been taking some time (I think you may have guessed this already!), but availability in the US of Shell Advance Ultra 4 and Shell Advance Racing X is currently pending US Trade authorities approval. They are expected to be available in early 2006, so look for them at your local Ducati dealership around that time. We will keep your details on file and let you know of developments.
Regards,
Shell Advance Biker helpdesk"