The Milestone Blog has posted a very in depth SBK X Q&A session. Looks like U.S. residents might see the game in Q3 this year.
"All the SBK bikes and riders are totally up-to-date with the current 2010 roster. All Superstock and Supersport, instead are up to date with 2009 season. This has both production and gameplay reasons: we make the models literally while the real ones are too, so it’s a huge effort, and since we have the career mode, we think it’s very nice to have some yearly progression inside the game."