Here's some hopeful news.
Apparently Vodaphone has already released a WM6.5 upgrade for the Touch Diamond 2.
What is really good about this is that is shows what version (build) of the OS is coming and what it will look like.
As anyone who has been flash WM6.5 ROMs on devices that are unlocked there are a lot of different looking builds out there.
http://wmpoweruser.com/?p=8578