Last summer, we used hockeyjerseysdirect.com. They weren't quite the cheapest, but they weren't far off, and they were the fastest to answer our questions. Totally happy with the service and quality. We asked them several rounds of questions before narrowing down what we wanted, and they were good about making it clear what the different options would do to the cost and quality.
I've seen these guys reccomended a lot for custom stuff over on Modsquad. http://bigstick.ca/
Don't know about customs and such, but they'll build jerseys to exactly what you want, with whatever quality level and options you so desire. You can even get a pro quality jersey if you want.
try toughjersey.com if you click on the sublimated tag and look at the harley jersey those are mine. I designed it with their help. Or I should say I gave them my idea for a hd jersey(we are sponsored by a harley dealer) and this is what their artist came up with. they have good customer service also.