Using HDHomerun with BeyondTV and MainLobby, but not MCE.
Works great! I can see the blend of the OTA HD and the DirecTV Sat listings in TVLobby and use MainLobby to orchestrate the switching of hardware / software so the end user doesn't need to know "where's my TV channel?"
I think HDHomeRun folks created a list of what QAM Cable channels you would expect to receive. Fairly new, so you might not have tripped on that yet.