Try posting at styleforum.net, there are a few regulars there who have vietnamese tailors. I've been to Saigon and used a tailor there, was about $250 for two suits including fabric, I copied a Jil Sander style suit and it was quite good. COmmunicating what you want will be the diffiiculty unless you can speak Viet. Make sure you get the best quality cloth, try to avoid the tourist tailors, whilst they may cater better for you, they are usually pricier. SOrry not so good in recommending tailors for you.