I can say from personal experience that is is very difficult to even source parts here in the states.
We try to source as much as we can here, and most of our manufacturing is right here in Detroit. We have had a few projects stall out because we can't find anyone in the states to do the work! That's right, we get alot of jobs just flat out no bid, so sometimes we have to look overseas for a component.
For the most part, its not a matter of cost, most of the US made and imported parts we get cost about the same, unfortunately its the lackluster sales and willinngness to work on a project that has hurt us from using more US made parts.
Mark