I have never seen any of Pentax's upper level cameras (k-7, k-5) locally. If you want to try before you buy, purchase the camera online (B&H, Adorama, Amazon) and then do a return should you not like the camera. I've done returns with Amazon w/o problems in the past and they often cover the return shipping.
Your other option is to rent it through BorrowLenses. They have K-5 bodies for rent and I think they charge $95 for a 3 day rental. You can complete the rental online and they can either mail it to you or you can pick up at one of their partner locations. Picking up is cheaper, plus Rayko Photo Center on 3rd St (SF) is one of their pickup locations. If you've never been to Rayko, they're a photo gallery and public darkroom. It'll make you want to shoot film