It would appear that as of this morning (2/9/10), there is a new local HD channel added to the Boston lineup. It's channel 515, which is the HD feed of the local Ion affiliate, finally! Though I am getting a message saying "You are not subscribed to this channel." From what I understand, this shouldn't require a subscription. Is there something I have to do first?
I also noticed that Rhode Island PBS (WSBE) in HD (I guess, the title just says WSBE PBS) is now available on 518 in the Boston area. I'm not sure if this was there before or if this was added when Ion was (which is now unlocked as of this afternoon).
The other thing that's always made me curious is the public digital and digital subchannels in the high 400's. In Boston, these are ThisTV (WHDH 7.2), the Ion subchannels (minus Worship, which was discontinued last week), WGBX, WGBH, the PBS subchannels, and one the Spanish subchanels, LATV. Yet, only WGBH (PBS 2) is available in HD, channel 502 (as well in analog SD on 2). Theoretically, if the high 400s were "digital" subchannels, they would be broadcasting digitally and thus inherently in HD for HD programs. But that's not the case. Neither WGBX 44 or WGBX 471 are HD, and there is no channel #544, so no way to watch WGBX in HD.