Posie's is one of the nicest shops I have ever visited it is not a fancy place but they build some very nice cars and yes a turn key car is expensive but they will sell you small parts and help you figure out how to use them. We stopped there a few years ago while on vacation and they showed us around thier entire operation, made us fell very welcome. Ken and his employees are true rodders and they build some great cars powered by nearly any thing you can think of. They built a very nice flathead with injection a few years ago, saw it at several shows. They are famous for their forward thinking and craftmanship.
As far as cost goes if you want a car built by one of the best and of magazine quality it is expensive.