This reminds me of Akihabara (Tokyo) in the early 1980s - I remember picking up a blue LED (8V drop?) - no one in the US had ever seen anything like it. Great article, going to have to add this to my "bucket list." I've dealt with Seeed Studios, and talked with them at Maker Faire in 2011 - good group of guys!
I was an expat working in SZ (Yantian) and used to go to this place with my team to get parts for prototypes/production. We called it Sai 4 ge 1 in Chinese. We setup a factory for an American company in Yantian. First time I have seen photos of this place outside of China. By the way, in Southern China most of the major cities have some type of place like this - smaller scale - where you can get just about anything electronic. What is strange is that this place you mention has all kinds of cool parts that I have never seen in the USA. For example, the strange little battery connectors for hand held stuff, housings for remotes and key fobs, and other stuff all at great prices.