Thanks!
Asking design studios is always a good bet, we (designers) are pretty friendly folks. ZURB has a job board[1] you should look into if you're down to spend a bit of coin to post there (peanuts compared to the value of a good designer).
Forrst[2] is a great resource: you can view designers' work, and thought/iteration process + communication skills (compare what you learn from this to a bunch of polished Dribbble shots).
Finally, if you see any companies that have awesome designers, hit up said designers and ask if they have any friends/colleagues/contemporaries they could recommend. They'll at least appreciate the fact that you're asking yourself, as opposed to going through some obnoxious recruitment firm; also, make it clear that you're not trying to steal them (unless, of course, you are).
I've tried Dribbble, but half of the people available "for hire" are moonlighting (not ideal and wound up with a lot of false starts) and when I put an ad on Authentic Jobs, I was flooded with extremely unqualified applicants.
I also tried Scoutzie and that was the worst of all of them, because it requires you to comb through a bunch of portfolios, and most weren't very good, and the filters weren't specific enough for skillsets.
Some top people hanging out there and you'll find good advice and resources as well.
Had not heard of sortfolio, thanks.