I've been looking into a possible switch to Dish, with the Hopper/Sling and Dish Anywhere. From what I've read so far, short of rooting your phone, and installing a hack to direct files to the SD card, there seems to be no way of getting them to the SD card. It seems I'd be limited to the phone's internal storage. I think I read it requires about 2gb of storage per hour of video, so seems like a perfect opportunity for SD card storage.
I would love to be proved wrong, however, and will follow this thread.
Don