Alright, I'm not sure if it's official.
but it's worth watching!

http://vimeo.com/4255076

so confusing

Sigh, they'll never learn. After 23 years Microsoft finally decided taskbar rearrangement might be a good idea. By Windows 42 we may actually have a user friendly windows customisation interface (what now is the register).

... so they might not even implement taskbar rearrangement. That's even more sad.

you can rearrange the taskbar in windows 7

How exactly do you want to rearrange the taskbar?
Changing its position: Works already with WinXP and did work in Win2k afaik
Reorganizing the order of the elements: like putting the quickstart icons right is indeed not possible in XP, at least I don't know how.

they are talking about changing the position of running applications on it.