Polka Dot Polly is a made to measure, online, uk-based dress shop. Polly can whip you up a dress to fit like a glove, with hundreds of fun fabrics to chose from. She also makes skirts, blouses and men's shirts. I'm really taken with this old fashioned fabric with a subtle TARDIS motif running through it.
And if Doctor Who isn't your thing, Polly has hundreds of fabrics to chose from. I'm sure if you sourced the correct amount of fabric of your own choice, she could work out a price for the frock of your dreams too.