We went to Keith Fagg and bought one but when we went to order them they couldn't get what we wanted so we went to Romano's. They were really helpful.
Another place to look is Johnson Tiles and they are having a sale at the moment. I didn't know about them until after we had started.
Another thing to start looking for is your accessories. It takes awhile to get the vanity in if they don't have one in stock.
I wanted a special shelf/soap holder that took ages to find as it was the same length as the tile.