If you ever travel to Tokyo, go to Akihabara (the "electric district") and you'll find stores like this everywhere. They're a hobbyist's dream. I wish we had more of these in the US.
I've heard Akihabara is a bit of an overpriced tech/gamer tourist trap, and that if you want to actually shop there are neighboring cities that are far cheaper.
Very true. Or you can find a local who can walk you through Akihabara and lead you to the actual good deals. A lot of the storefronts on the main strip will be overpriced, but there are good deals to be found if you wander off the main streets.