Light in the Box
Ordered one bridesmaid's dress from LitB as a test: it arrived yesterday, and I'm really pleased. Good quality dressmaking, the colour is as expected, and it fits absolutely beautifully. The only slight niggle is the amount of padding in the boobs, but I think that should be easily removed.
Once you add customs, it's not as super-cheap as it first appears, but still much much better value than you'd pay for a dress of the same quality from specialist shops for bridesmaids.
I'd happily recommend them to other B2Bs thinking about ordering, and will now be getting the other three through their made to measure service.