Not having local (or national) PBS HD via satellite pisses me off too. Sure, the HR20 does a great job of seamlessly integrating OTA with satellite... IF you can get the locals via antenna. It's very marginal for me, and I don't want to set it to record something and go to watch the show later and find out it was a bad OTA day and the recording is blank. I could probably get OTA reliably with a rooftop antenna, but why should I have to do that, that's why I subscribe to DirecTV.
I emailed DirecTV about this just about a week ago, and got a fairly generic response that was completely uninformative (just said that they're evaluating the possibility of carrying local PBS HD in the future). I am curious about that rumor of PBS insisting they carry all subchannels. I guess I can see some motivation for that, but I think I'd rather just get the main PBS HD channel than no PBS HD at all.