Given that these things are getting hard to get due to their popularity, I'd say if you can find one, and then get the dealer to knock anything off, just grab it. $56xx... okay, say $5500 out the door (if that includes sales tax)... and go ride and enjoy it. Is it worth the frustration of going dealer to dealer over a couple hundred dollars? :)
The only "discounts" you might be able to get will be on dealer fees like "assembly" or "delivery" (not destination)... so really, best you're gonna do is maybe $100-200 off, IMO.
Re: Washington vs Oregon... wherever you register it depends on sales tax. If you live in Oregon, you can buy in Washington and still pay no sales tax. But if you buy it in Oregon and live in Washington, they'll hit you for sales tax when you register it... unless you can use an Oregon address and get Oregon plates.
'12 Suzuki V-Strom DL650
'96 Suzuki DR650
'10 Kawasaki KLX351S #320
'01 Yamaha FZ1