AMD just released their new monster, the 12-core Opteron, meaning that a 8- and 12-core Phenoms aren't that far away either. These Opterons can run in 4p configurations too, that is 48 cores on a single board.

The question I have is, will Vegas even be able to make efficient use of 12 cores?
I can only assume you need a serious hard disk system and lots of fast RAM to keep that many cores happy when rendering video.