Sprint may host it Dish has been working with Sprint's to host it but they had the interference issues, which now appear to be resolved. Sprint's new Vision infrastructure is designed to pop in cards for 3rd party networks, sorta like telcom hotel thing but for cellsites.
My guess is that Dish will work with Sprint to host it but Dish may eventually get out of biz and Sprint will end up acquiring the Dish spectrum in the end.
Under this scenario, Sprint doesn't really need to buy Clearwire. Dish spectrum is more desirable.