Just see this new post at the DPR and I think it is worth reading for what it has been tested and shared:-
http://forums.dpreview.com/forums/readflat.asp?forum=1036&thread=33562896
To my surprise, the GP Recyko+ doesn't work in his K-x and he tested two brand new sets of 4!
But in fact, as I pointed out when the K-x was first announced, NiMH is actually not a suitable solution for a super high drain electronic device like the K-x especially for its LiveView and Video functions. Now, the above K-x user has found exactly the same for what he tells.
Btw, I think I have even more NiMH models in my home than that new K-x user "thank" to Pentax! For what I have used and tested over these six years, I recommend Camelion AlwaysReady. If you have faced the same battery issue with your Pentax AA-battery DSLR especially the new K-x, try the AlwaysReady if you can get it. However and of course, still don't expect Lithium rechargeables' reliability and longevity even with the AlwaysReady. Although it is just better (or even the best amongst all different NiMH models by different manufacturers I have, including the Eneloop), it will STILL do NO Magic as it is Just and Still NiMH after all!
Maybe you can try the latest NiZn AA rechargeables, if you can find it, which requires new matching charger for the new battery type. For more details, read this:-
http://ricehigh.blogspot.com/2009/10/six-years-of-aa-battery-pentax-dslrs.html#IDComment38620548
But then self-discharging of this new-type NiZn is yet again an annoying issue - the old classic problem of those conventional NiMH and NiCd rechargeables.
Last but not least, you can read also the latest battery issue reports by K-x users at Ned Bunnell:-
http://nedbunnell.blogspot.com/2009/10/k-x-battery-notes.html
Note the first two comments..