On the "Eastern Arc" when a HD version of a local is available they dont carry the SD version..I suspect they will eventually do the same thing with the rest of the HD channels thus eliminating the need for a channel in the 9000 range
I would bet they would do it now if they could. After all, all the receivers on EA are MPEG-4 HD receivers. But, I suspect they are contractually required to carry the SD version of the channels (and as in the case of Disney pay for both the SD and HD version). Until the programming providers modernize and stop forcing the SD version, I suspect the duplicate channels will be with us for a long time.