Absolutely!
I get all my pants, shorts, dresses done with #21 (in the fabric market) and then all my shirts (i.e. linen shirts I get here b/c it's so hot and great for traveling!) I get with tailor #5099 - she's located outside the fabric market - same floor.
Lots of AMericans go to #21 and the tailor's assistants all speak pretty good english. I find that their best work is when I give them an actual item and they just copy it. Remember to tell them all the details of the new garment you want made - right up to the buttons. The more explicit the better. #21 has done a great job on pants, my husband's work pants, shorts and dresses.
Once you start going and begin to build a relationship with the assistants/tailors, they will even lessen the prices for you. We've gotten some amazing deals!