Well, yes it does work. I have install the same sidebar I put on here and it works. Its transparent and has the clock, RSS, and search and something else, I'm looking at it now.
No I haven't tried it yet. I've been angry with Vista lately and moved back to XP as you seen I've been having trouble getting sound which I recently fixed. But still I could not get transparency because I have a 32meg vid card not a 64meg vid card (minimum requirement). On top of that the sidebar was empty. That was the last straw for me and I moved back to XP for now at least. I may go back with the November or October builds.
Did you put the gadgets for the sidebar into the prts folder under the users/admin account? From there you have to manually load then from the sidebar.