According to my intel, offers were supposed to go out before Match Day. Not sure if they experienced a delay or not.
Thank you notes are a polite gesture, but only the admissions office, NOT the committee, read them. They have no bearing on your candidacy.
Also, don't let Sactown bum you out! We're close enough to SF/Tahoe that you can get away for a weekend regularly, and without the expensive cost of living! Also, its not as bad once you get used to it, even if you come from a larger city. Plus the people here are super cool B-)