solidsignal.com or weaknees.com. I've purchased one box from company and I've been very pleased.
I had to order from an online retailer because DTV refused to guarantee me a NEW receiver if I were to have ordered through them. Complete BS.
If I'm going to drop 2 or 3 bills on an HD-DVR box, as a customer - I expect the unit to be BRAND NEW, not some refurbished junk. As a new customer with DTV (few months), this is my only gripe thus far with their customer service.