I would guess the Sac dollar being in limbo is delaying most sets. There's more info in the Sac 2008 thread on this page.
The Silver State quarters are also available, as well as the Presidential Dollar proofs. I had the same question though, because I got this http://catalog.usmint.gov/webapp/wc...ctId=14212&langId=-1&parent_category_rn=10211 In both silver and regular for 2007, and I was wanting to get 2008, but the set including the nickel, penny, dime, half, and sac dollar isnt out yet. I was told that its because those dont come out until the 2nd half of the year, but I'm not sure if thats true. I have also heard that there is some kind of debate on whether the mint can put the Sac in there for some reason.