As of a couple days ago, ATI released their next drivers for Linux. The drivers were previously announced to be versioned 8.43.x but ATI has converted to a new numbering system that follows the popular YEAR.MONTH notation. The 7.11 drivers therefore accurately represent their release date in November, 2007 and are what would have been 8.43.x.
Anyway, there isn't a Gentoo ebuild for these drivers and there may never be one. When I checked, there wasn't even a bug filed to have one created. The 8.42.3 drivers eventually made it into portage as a masked package (~x86) with the consensus that they will never be marked stable. The 7.11 drivers will probably not even make it that far since the list of changes is rather minimal and nobody has posted any benefit to upgrading to them. You can read the Gentoo forum on the subject for more details if you like.
Anyway, it looks like we'll be waiting for 8.1, or whatever the next release date happens to be, to find out if we finally get a faster AIGLX implementation for X.org.
Update: Well, I guess I called that one wrong. This morning my portage update contained an ebuild for ati-driver 8.433, which is the 7.11 driver I talked about in the article. I still don't think there is much benefit to upgrading though.