HD package has a base commitment of Total Choice. Regional Sports Channels should be included with TC or TC+. NFL Sunday Ticket, as contracted by the NFL and DirecTV, can be purchased without any other commitments.
You can get HD or other packages on Dish without having a basic package, but have to pay an additional $5 for not having the basic package (AT 50) in which is only $25. DirecTv's basic package is about $10 higher in which is similar to Dish's AT 100.