Butcher Shop Cafe in Kenmore... open tues-sat 11- 7p... place has turned into a real gem. If you are having duck (or any fowl... or fine beef) at a fine restaurant it is probably coming from here. Ask for Bill. 425.485.4658
With head? I've seen them at HMart in Lynnwood. I don't recall whether the ones at Ranch 99 Edmonds have their heads. Probably so (the deli bbq ones do). I've also seen extra feet (boned), gizzards, and tongues at 99.
I've gotten mine at Viet Wah (12th and Jackson in the I-District). They're cheap, raised cheap, but always there. If you're in a rush and want an already-finished duck, the BBQ shop on 12th around the corner is almost the same price as the uncooked duck itself.