Over the last few weeks I've seen a few posts about the new Hot-Add CPU feature in SQL Server 2008. I think it's pretty cool and I've been wanting something like this for years. I managed a large IBM server at one point with AIX (manager managed, not technical managed) and we had the ability to move resources in and out of both AIX and DB2 without restarting the server. It was pretty cool and we had a hyervisor that handled all virtual machines to make this possible. 

I've been wanting this on Windows, and SQL Server, for some time. I'd like to see memory management as well, but one question I had was whether or not there was "hot subtract" as well. If I move more CPU resources over, presumably using some hypervisor/virtual machine technology, can I then get them out of there if my load decreases?

No one's given me an answer, though maybe I'll learn something at the MVP Summit in April.