Here is his latest "Lumolabs" test results and a shootout for the above DSLRs:-
http://falklumo.blogspot.com/2009/12/lumolabs-sensors-of-nikon-d700-d5000.html
Well, as well expected, if SNRs are measured, the Full Frame wins. But if you are to check the Dynamic Range by shooting grey stepping, surprisingly, the K-x wins (but actually the actual SNR could be lower).
It is interested to find out again the overall sensor IQs of the D5000 and K-x are close enough, as they share the same sensor (as widely believed).
As for the upcoming DxOMark results for the K-x, I expect they are to be similar and close enough to those of the D90 and D5000 and of course will blow the K-7 out of the water as such. Let's see if this would be true later on when DxOLabs publish their new results! :-)
Read Also:-
DxO Scores Comparison (Pentax Against Others)