Asian tailors can be a good option and value - assuming you are local to them (or they visit your city regularly) and you are comfortable with a high level of directed involvement and oversight in the bespoke process.
In my recent trip to Asia, my first stop was Hong Kong. I visited two tailors, A-Man Hing Cheong and Tux & Collars. A-Man had a nice selection of British fabrics (John Hardy among others). I chatted with a fellow named Norman and, partially ignoring my own advice above, I ended up ordering a tweed jacket made up in a 16oz gunclub from the John Hardy Alsport book - in the broader interests of sartorial research of course.
I also attempted to visit Tux and Collars, whose head cutter purportedly trained in Naples. When I visited the address in the Pacific House across from Harvey Nichols, the store was shuttered and had either moved or closed. According to the lobby security guard, they had moved out a couple of months before my visit. But unfortunately he did not have a forwarding address or other contact details.
Vietnam is quickly moving forward in becoming a global textile and apparel player. In 2008, Vietnam's garment and textile industry is expected to hit $9.5B in exports and employ some 2 million people according to Vietnam News (10/01/08). The Vietnam Garment and Textile Association expects to be in the top 5 globally by 2015-20. The US is the top importer of Vietnamese garments and textiles, followed by the European Union, Japan and Russia.
In Vietnam, I visited a couple of tailors: Dung (pronounced yung) Tailor in Ho Chi Minh City and Duc Tailor in Hanoi. Dung has been in business since 1985 and appears to be a genuine bench tailor. Shirts range from 25 to 45 USD and take two weeks. Suits go from 160 to 500 USD and take roughly 3 weeks. Incidentally, the concierge at the Park Hyatt Saigon recommended a couple of tailors, Cao Minh and Dung.
Up north in Hanoi, I visited Duc Tailor just north of Hoan Kiem lake. When I walked in, I saw a fitter making marks on a customer's basted jacket (no sleeves, just the body) and a cutter nearby marking and cutting cloth without a pattern (a technique known as "rock of eye"). He traced out the pattern with chalk directly on the cloth and then cut the cloth. The suits appear to be canvassed based on the basted jacket I saw.
There were four shelves of in-stock suitings arranged by price): $500, $400, $300 and $200. The selvedges appear to be of Italian origin. One selvedge read Garavino which I am not familiar with but I also saw a Dormeuil Amadeus book. Suits take 2-3 days. Pants have a price range depending on cloth: $50, $70, $100 and $120. Shirts start at $25.
Given the tropical climate and limited time, I decided to order a casual shirt short-sleeved shirt, which would be ready at 6pm the same day. I ordered a band collar linen shirt and initially sketched a picture of the band collar. But then I spotted a copy of the spring 2008 issue of Menswear magazine on one of the shelves and found a picture of the collar style I was looking for.
As the cutter took my measurements, he recognized I was wearing a custom shirt (made by Freddy Vandecasteele) and asked if he should just copy the measurements which he did (chest, abdomen, waist and shirt length). I requested small adjustments to the sleeve length, overall length of the shirt body and band collar height.
The area just south of Duc tailor is a busy retail area for RTW sandals and shoes as well as luggage and backpacks (Cau Go and Lo Su/Hang Dou streets).