I'm fairly new to the Portland/Vancouver area (from Seattle) and every Thai restaurant seems to have pad thai drowning in orangey-red sauce--made with ketchup or tomato paste. On a brief visit to Bangkok last year, I ate pad thai at 3 different places and never experienced this sauce. The closest I have found to authentic is at Kinnaree and May in Seattle. Whenever I am brave enough to ask what's up with the orange sauce, I am told it's a regional thing or it's the tamarind paste. I keep hoping I will luck upon some place down here that will say, "Since you asked, you must be a connoisseur of the real stuff. I will bring you some right away!"