with every camera and lenses u can experience focus issues
its not a big deal, send ur lenses and body to warranty, get them calibrated
used k100ds and k10d, now im using k-r. i can say im impressed with af speed and accuracy under low light.af-c is working much more better than old k100ds n k10d aswell. handling of camera is better compared to k-x. and imo u should stop thinking about getting it, just buy it
u ll be happy.
but keep in mind, u cant really compare focus speed of k-r with a 7d with L glass :] all my thoughts are inside the pentax brand.