Great job on the write up of the Multiple Exposure mode on the K3. It's nice to see it documented as the it's one of the best Multiple Exposures of any camera around now. For me, as i shoot multiple exposures 80-90 percent of the time, the K3's new M.E mode made it worth the upgrade alone. The fact that it is now in the drive mode makes life so much easier. What was annoying with the K5 M.E. mode was if you had shot 3 out 5 images (or whatever) and felt it was enough and cancelled the remaining exposures, when then again selecting M.E mode it would take one shot and knock out of a sequence of multiple exposures. This was a real nuisance. Now with the K3, that's no longer a problem.
The 'bright blend' composite mode is also a major added bonus and seems to open up a whole new creative mode. In particular i found this mode works amazingly for blending a sequence of Intentional Camera Movement M.E's. The way the pixels interact is massively different to the standard 'average' and additive' composite modes.
In a review of the K3 in Imaging Resource, it was stated that there was the option to select an image already stored on the camera as the first shot in a new series of multiple exposures at another time. I contacted the site and Pentax at the same time as i couldn't find any other info to confirm the K3 could do it. Pentax got back to me before the reviewer to confirm that it was incorrect but that they would forward it to the developers who may add it in a firmware update. Only the Canon 5d mark iii and 1D mark 'whatever the latest one is" has this feature now i believe. This would open a whole other door of creating images that would normally require Photoshop.
A wee example of the 5 M.E.s (four of them 1 second) in bright blend mode in the forest.