Interesting thread. I have had shirts tailored for me by various tailors both over the net and locally.
Of course you can get very good deals by buying in the Far East (China, Thailand, Singapore, HK). In the end I decided to stick with local tailors though. Sure they cost a lot more but they are here and have to look me in the eyes if something turns out flawed. I am quite picky about my clothes so I prefer to be able to discuss everything beforehand and also afterwards if need be.
Just my two cents.
Valerian