Troy, when I heard SQL 2000 wasn't supported, I was 1/2 happy and 1/2 worried. Happy in the fact that we would have a reason to upgrade and maybe move the SQL database off the physical VC server and create a VM for it which would be better, but also worried because I knew that could totally kill any movement to 4.0 due to funding. Mainly the worried part won through so far because I got the question, well why do we really need to upgrade to vSphere 4? Besides the small, faster, a little more reliable, and new features (which would probably wouldn't use) I didn't have much to offer so we'll see about that. We shall see.
I did have difficulty connecting UM to my remote SQL server in my R/D lab but I'm not sure if that was due to a bad install on my part of SQL / configuration or something to do with SQL 2000 or what. Obviously it works attached to a remote sql server but I broke down and re-installed it using the MSDE version it installs on the local machine for you.