I have no knowledge on the introductions on PMA 2010 as a regular reader of this forum.
What I do know is that Pentax is introducing follow up models more or less each year, (12+ months) where the K-7 (follow up of the K20D before that K10D) and the K-x (follow up of the K-m, before that K200D) is out of sync by approxiamtely 6 months.
Looking back over the years 2007 - 2010, I'd expect a K-7 follow up fall this year and a K-x follow up late 2010, early 2011.
After that you need to wait 3 months for Pentax to fix the firmware to an acceptable level.
I think Pentax engineers in general do not get enough time to deliver the right firmware quality at introduction.
The K10D had numerous problems, K20D shake reduction, K-7 green line & hot pixel issues, K-x battery issue.
Also if you wait that long the price comes down 10%.
I guess you may want to try the camera's in a local store now and if you buy one, you will have at least half a year extra fun with your new camera.
Of course you can always wait another year, the model after will have better features and specs for sure