I used some DF exposed timbers and T&G decking in my house a few years back. We found several sources, but my recollection was that the best price was from New River Building Supply near Boone.
I used local red oak for the trim in my place (with a cherry stain, I thought it had enough contrast to complement the DF nicely), but the DF with an oil finish looked great for the timbers and decking.
I got on a email list for a supplier on the west coast, and yeah, it breaks my heart to see how cheap that stuff is out there compared to how much you have to pay after shipping here. I'll second the thought about using something local for trim--for the price of DF, you can get some interesting stuff if you have the time and are willing to work with a sawyer.