https://www.wearefactoryfive.com/

Bike shop in Shanghai owned by a Canadian I went to school with. I just bought a frame from them. Great products at half the price of what you'd pay in North America, made for them by a factory in south China. Let me just say, I know a thing or two about bikes and their welds are unbelievable. Their smooth welded aluminum frames are better done than the old US made Cannondales, and on their steel frames, some of the best TIG welding I've ever seen. They do fillet brazing and lugged too. Their site lists only fixed gear frames but they do all types of frames upon request.

The only caveat is geometry. I'd stick with a North American builder if you want a true custom dimension frame.

I can't vouch for the builder in the OP's link. I wouldn't dismiss Chinese builders categorically. There's great stuff and crap stuff coming from this country.