There once was a shop in Hollywood, Florida that only sold Atari 8-bits and Commodire 8-bits. It was at the now closed Fashion Center Mall. That was a great place. They'd let you play almost any game, including a few that used a modem. It was like War Games, only I didn't really understand what was going on because I was too young. But I do remember being floored by Shamus on the 800.
Anyway, I don't know what the name of this store was, and doubt it was what you're looking for. But it was a great, short lived shop in South Florida in the late 1970s and early 1980s. There might be photos floating around on the web.