I think those channels in the 53xx range are for the Dish Latino HD package. For whatever reason the HD Ultimate channels were in the 94xx range and the Essential channels in the 53xx. I think they're finally realizing this and are putting the HD Ultimate channels in the 53xx range.
HDNet Movies
MGM
Smithsonian
Universal
WFN
I'm still trying to figure out what the other 2 channels are.
Randall - I signed up for the 3 free months of Ultimate Promo so that my wife could try FashionTV-HD.
The above channels already have 53xx numbers:
HDNet Movies - 5351
MGM - 5369
Smithsonian - no longer on Dish Network in any package
Universal - 5354
WFN - 5372
and the other Ultimate channels:
MavTV - 5405
Logo - 5307
FashionTV - 5304
so the 7 channels being mapped to 53xx means that there is a good likelihood of getting more new National HD - because I don't remember them mapping channels to Dish Latino HD until they were ready to make them available. The recent addition of SpikeHD and FxHD despite that Charlie Chat comment about the channels not being up for contract renewal yet, implies that the new Programming team is taking a different tact in negotiations, a tact that is resonating more with the negotiators on the other end of the table. So, totally a guess - but I would think that the missing Rainbow channels is a good guess.