Yes there is a noncommercial student station that is using their college station's HD-2 to feed a secondary analog FM station which is licensed as a translator. They regularly announce the analog frequency but only occasionally mention they're also on the other station's HD-2. There has been some discussion about whether this is legal since the translator is broadcasting original programming but its noncommercial status apparently lets them do this.
Entercom is letting a noncommercial Christian Contemporary station (WAY-FM) use an HD-2 to feed yet another a translator which is broadcasting original programming. I don't know if Entercom is getting compensated for it.
It's likely that Entercom is using the HD-2 "Northwest Bands Only" station to feed programming to a disused 5 KW AM station they got for cheap but don't want to pull the plug on. An HD Radio at the transmitter is a lot cheaper than a real STL feed. The HD Radio station ID reminds us that it is also on 910 AM in case we get tired of the crystal clear digital reception.
(And Portland rarely has thunderstorms!)
NOW: my post on AVS Forum.
NEXT: someone else's post on AVS Forum.