Just an update on this for anyone who's interested (though we Pentxaians are a little thin on the ground).
After all the hooha in the DPReview forums about the Canon 5D some idea of what Pentax are planning has been bandied about.
From a hitherto reliable source, it seems Pentax are focusing (no pun intended) on the bottom end of the market for the forseeable future, with the exception of the previously announced 645D. Any idea about FF from them seems to be at least a couple of years away and there's nothing in the rumour mill regarding IS
Looks like the upgrade to the D won't be here 'til next Spring at the earliest and it will likely still be APS-C with no IS.
But, reading between the lines, it's possible that once the 645D is into it's 2nd generation, the sensor from that (which is FF35mm size and will be made by Kodak) could appear in a FF 35mm DSLR.
Then again they may completely surprise us all!!
--NN