I can't agree enough with this. I help startups find designers through my site (http://folyo.me), and it's been all but impossible to find great designers available in the bay area.
On the other hand, the rest of the country (and the world) has tons of really good designers, some of which struggle to find work.
So far the companies who have gone the remote route haven't regretted it, and they've been able to avoid spending countless hours searching for a local hire.