how to chose/build a new bike?

[caligurl]

ok... so i know you can walk into any bike store and pick a bike and get fitted to it...

but what is the process if you want to "build your own" sorta.. not really put it together myself.. but pick all the pieces and parts and have the LBS put it together...

the LBS isn't a fit king.. more of a small town shop.. how do you know what size of everything you need? you can't sit on it like you can a store bought bike... so where do you start?

go to a serrotta fit place? but aren't they just going to tell you to get a custom if you are off even a little centimeter from that optimum fit?