Ok so don't shoot me.
We loaded an XP over a win2k last week just for fun. It was.....figuring out why xp would not load either in upgrade or install. I found some directory it did not like on the vendor partition and once I blew that away it loaded.
So once it got going (odd, on a relatively fast system it took more than twice the time for 2k to load on the same box) it was embarrassingly easy to set up. I don't think I can look at the desktop etc for too long as it seems....so.....preschool in layout. It inserted itself in the multidomain structure without a hitch.
I'll sniff it next week and check its chatter.