PK Racing in Fairfax is great. Chris does a really good fit. Plan to spend about 2 hours there. He will fit you to an existing bike or fit you and give you specs to order a bike from anywhere. He does sell Serotta there, but doesn't push that at all. He charges enough on the bike fit that it doesn't really matter.

Also Endurance Mill Valley does a good fit as well. They use a laser set up. I think the cost is comparable.