Hey,
If you are looking for the reputed sublimated clothing manufacturer in USA, Australia, UK, I recommend you to once give a look at Oasis Sublimation. I got to know about them from my friends, who had bought wholesale sublimated tshirts from them at reasonable price with their own logo and design for their own clothing stores. My friends also told me that their quality of products were too good. You can check out them if you are interested in customizable clothing.

Website:- www.oasissublimation.com