This was promised at the introduction. I am eagerly awaiting its arrival. Whenever I visit Dish's site for more information it always says "Coming Soon"
I have the Dish ViP922 Duo with Sling. It's got a decently large disk (1TB) and it supports Sling. My complaints are the number of times that the device just flat out does not record a show. Its almost as if it forgot (as if that were possible). It's happened at least 7 times since I rejoined Dish in late 2010.
I am looking forward to the Hopper because it looks to be what I wanted the 922 to have been in the first place. I hope the processor is good and powerful.