I actually started with the *istDs, then K20D, then K-7, so haven't used a K10D sorry.
Yes I see the K-7 as competent in sports, but of course I have no experience with anything else. Someone else used to maybe a C or N top model may form a different opinion after using the K-7. I wouldn't say it's great or fantastic though, but again tricky to say without experience of another make of camera.
The K-7 AF is definitely faster than the K20D, I now get probably double the number of keepers from a game. In good light, that is sunny, I am sometimes quite amazed at the K-7's AF speed, getting several in-focus shots of someone running (not straight at me usually, but an angled run, so not "across" me either). My last game was a record, I got 99 keepers. This is with a Sigma 70-200/f2.8 with a Sigma 1.4x TC on. Without the TC it's even better.
No way can I afford, or justify, two systems. I think your idea of the K-7 as a family-type camera is a good one. The problem with larger cameras is they can tend to be left behind when you head out the door, I love the K-7 size. Currently my dream lens, the Sigma 120-300/f2.8, is not even available in Pentax mount, not that I could afford it! But nice to have that option!
Personally I wouldn't start a new forum, there's sooo many out there already.
Originally posted by Bart Thanks Bart, those 3 appear to be the top ones. There doesn't appear to be one dominant Nikon one like this for Pentax or POTN for Canon.