I've seen this before, many times for IFC shows, and GSN's Improv-a-ganza before the channel went HD. I thought maybe it meant we'd be getting IFC in HD soon, but the ads began last year with Portlandia and Onion News Network and we still haven't gotten it. And yes, they were Dish promos with the Dish channel number.
For a long time our local CBS channel would have promos for their upcoming evening newcast in HD. Problem was the actual newscast was not in HD....I think it was because the other three networks were in HD.