Chinese ZOL has done many crop comparisons amongst D800E, D800 and 645D based on IR's comparometer's studio test scene shots.
Via DSLR Maniac (Japanese)
Quick links for different comparisons as follows:-
D800E vs D800
It seems that the once IQ and resolution king (at low ISO) of the 645D now wins little over the D800/E and thus Pentax should update their 645D with a new sensor soonest so as to maintain the gap in the past (and here is a latest rumour about it).
Btw, from the moire test at different spatial frequencies, it seems that the AA (Anti-Aliasing, aka Blurring) filter is still useful so as to avoid lower frequency moires that could appear once the Nyquist limit is exceeded. It can be seen no software (neither any RAW convertor nor in-camera JPEG engine) is helpful to eliminate those, without the existence of a hardware AA filter! Well, Nyquist theory must be obeyed! Right?
Besides, the K-01 studio comparison has also been published at the DPR. Again, one can compare endlessly for any part of the single test scene against any previously tested camera over there!
http://www.dpreview.com/news/2012/05/03/Pentax-K-01-Studio-Samples
I haven't done any further measurbation myself, coz I don't have much time to do so. But there is one done by someone with some comparison crops posted:-
http://forum.pentaxfans.net/thread-125995-1-1.html (Traditional Chinese)
It seems that the K-01 is close to K-5 in IQ but it is much cooked, i.e., more saturated, more/stronger noise reduction, more sharpening and etc.