I make all my shirts and a suit from Joe's Tailor. They have made suits for many international business man too.
I would never go anywhere else. Prices may be a little more than compared to other tailor's in Singapore, however i do not think that they are more than the tailor's in the West.
There is a very popular tailor located at Raffles Hotel, called CYC if i am not wrong, never been there, but they are known to be the tailor for local politicians etc, prices are known to be very high too.
You could try to drop an email to Joe's, to check on the prices and if they provide what you want first.
Link: http://www.joetailor.com/index.html