I was up in Seattle last year attending a good friend's wedding and I had a day where no one was really available to hang out, so I did some Seattle exploring. I happened upon the small store front that Slate operates out of. Had a great cappuccino and picked up a small bag of their beans. Expensive for the amount offered, but still a good bean if you're in the area.
Slate Coffee Roasters
5413 6th Ave NW
Seattle, WA 98107