I've found interesting page recently:
http://bighugelabs.com/flickr/topcameras.php
This is weekly statistics on camera usage at Flickr based on EXIF analysis of more than 10000 photos daily. There is top 100 by camera model and top 100 by manufacturer. I can't see any Pentax camera in the first top, but the manufacturers top placed Pentax on the 9th position in the first week of December. A week later it was on the 10th line.
On PBase Pentax K10D was at the first line in the "Hot cameras" top, but lost one position for the Canon 5D. It now has 43 users and 390 pictures counted.