Well that sure didn't take too long. Looks like the T-Mobile HTC HD2 (aka WM6.5's last hurrah) has received a ROM update.
Slight word of caution: we're hearing this isn't 100% officially public yet, but perhaps the final ROM for T-Mo employees/testers, etc. So expect an "official" announcement next week by T-Mobile and HTC on this exact update.
The OS build is bumped to 21892 (a very good build, we might add), updated radio, updated Swype , reportedly more stable and responsive (via XDA forum) and finally, it includes a new app to see your account information.
If you want to know all of the software changes, here ya go (not for the faint of heart!).
Update: HTC pulled it :-/
Update II: T-Mobile will make the update official on the 18th!
[via TMoNews and PPCGeeks forums]