I hope you find one. I know Sony stopped making those 7 pin to rca digital cables once they discontinued making portable DAT recorders. Most online retailers such as Oade, Sonic Sense, etc. have a limited number of cables left but they have no plans on making more cables because Sony does not make the 7 pin connection piece. I think Core Sound (in New Jersey) makes their own cable but they do not use Sony's connection piece. They make their own connector which is not as good as Sony's connector. Sony's 7 pin has a "casing" around the pins to somewhat protect them from being bent or broken. Core Sound's cable leaves them exposed.
Good luck, I would be pleasantly surprised if Best Buy or some other local retailer had those cables.