Hang in there with your HD7. I know it seems real disappointing right now, but look at T-Mobile and their situation:
1) They just crawled out from the AT&T purchase fiasco. Truthfully, how could this company look into 2012 and have any consistent idea of products or devices when they had no clue where they would be in ownership? Had it gone through, it would have been even worse, as AT&T would have had to dump customers and markets to make it work. I am surprised they have the Radar and the 710 with all that uncertainty.
2) T-Mo has been very supportive of WP, so you know it will continue. First with the Mango device in the US? Radar on T-Mo. First with a Nokia in the US? 710 on T-Mo. Wasn't the HD7 the first W7? (Pretty sure.) That kind of loyalty will be rewarded.
3) At this point, why not wait a few more months with a phone you at least still like on the carrier you prefer to see what Apollo brings T-Mo's way? You may not have to comprimise even a little bit. You might end up with a MONSTER WP8. I would gamble on that. As a matter of a fact, I did- holding out to see what goodies AT&T and WP would produce, knowing that AT&T was a good supporter with a good history. I got my Focus S for a penny.
Hold in there, buddy. Come off the ledge. It will be alright.......