Off topic a bit since the OP was talking about a DS, but what do people think about cleaning the sensors on the K100/K10?

I know theoretically this shouldn't be needed on the K10 because of DR, but the K100 has no such luxury.

I'm not that worried about damage to the CCD, as I think the low pass filter covering it is pretty tough, its the various components of the anti-shake system which concern me.

I think if my K10 ever manages to get dust attached to itself it'll go into the shop, I'm too much of a coward!

wasn't the 645D supposed to be full frame 6x4 though? so it's sensor wouldn't fit in a K mount body.

the lens isn't going to be any worse than it was 2 years ago.

Obviously being a K series lens it wouldn't be the best choice on a DSLR unless you like full manual mode, but it should mate to your MX very nicely, being a similar age.

The A series 28mm F2.8 is pretty reasonable too, more common and cheaper although a little wider. The added bonus with an A series lens is its ability to work with all modes on a DSLR (except for AF of course).