Kiito is a bespoke tailor on Rosmead Place. They do excellent bespoke work ranging from suits (Rs. 16,000 upwards) to shirts and trousers (Rs. 3,000 upwards). They have material or you can bring your own. The main thing that makes Kiito our recommendation is the service provided by Damith Cooray and his wife.
Background
Colombo has a lot of affordable tailories (is that the word?) that can turn out pretty good suits and stuff, with direction. But that's the rub. With bespoke tailoring, communication between the client and tailor is key. The awesomely named Gaylord (Galle Road) and Hercules (Havelock Road) can do suits and things, but it's a bit of a chop shop in there, a lot of people coming and going, and to get them to do something to modern tastes takes a lot of effort. Raheem's on Issipathana (off Havelock Road) has a young and voluble manager who you can talk to, but he seems to spend all of his attention talking to the many women that drop in.
Kiito is different cause it's not a bustling chop-shop and Damith is a highly intelligent guy to work with. Most guys actually don't know what they want and he's a more helpful guide than the disinterested guys at, say, Hercules.