[Keefla]

Its an expandable system, the main box is standalone with DVR, the add-ons interface with it like an old 'dummy terminal' computer system and literally only contain a basic processor and video board. Its not 4 separate DVR's per se. (i.e. you only really need the main DVR w/integrated receiver if you only want 1 DVR). You pay for what you add on (as per usual the main cost is the DVR/Reciever however, the add on terminals are cheap).

Other options may be available but you asked about anyone who had DirecTV, and this is what i have, and with my research its our only option. Works great thow. Im pretty sure they make it difficult to interface aftermarket systems to work with their receiver. Any information to the contrary is welcomed however.

Best regards,
Keefla