I don't know much about Portland, but PS is the one that came to mind originally... I mean, it's a fairly open environment, and everyone who went to con knows where it is (besides me because when I went to con, I was one of the lucky people who wasn't able to see where we were going... My friend decided to turn the middle seat in his van around so that the people sitting in it could see the people in the back seat, thus making it impossible to see where we were going, but I can get directions to just about anywhere, so it doesn't really matter to me) But let's see, what about where they hold the saturday market? that seems to be a fairly wide open space.