There was a picture floating around for a while of the "HR21 Professional Series DVR". IIRC, it was black. It has no OTA tuner(s) and would cost $$$$. But it does give a bigger HDD, and more output options for audio.
Not that I have seen. I believe one was spotted at the CE show in Vegas this year, but it was a reciever for the business accounts like a (sports bar).
The HR21 shown @ CEDIA in Sept. was Black which also corresponds to the new D* Q4 Sales Guides (I work for a dealer) that we received yesterday in the mail. It shows a black DVR and states it is the new HR21
There is a black (glossy) HR21 coming out. It has been in field test for a while but the cat hasn't been let out of the bag until today http://hr20.dbstalk.com/docs/hr21_firstlook.pdf. Like the recently-announced H21 receiver, it does NOT include OTA tuners, so won't be suitable for everyone.