Hi Buddha,
+1 for the Contax conversion. I've done a quick and dirty one on the Contax Planar 1.7/50. Just loosen the 3 most backward screws (that's behind the flange), put some spacer material in between, fasten screws, done. That makes for a lens which can be mounted and used (on K100D) but for security the minimum should be a drilled hole to accustom the PK-locking pin.
Contax is a tad further out with infinity (sometimes goes, mostly doesn't). On the 1.7/50 it is easy to unscrew the name ring and adjust infinity.
I've also done an irreversible M42 conversion to a Leica Summicron R 2/50 1st version. Quite brutal, but for Leica and Contax there is a very nice offering from
Leitax (click the left side logos to get to the desired conversion)
AFAIR Aegisphan has done a lot of spreading the word on this forum about converting those renegades to the Pentax-church :-)
He posted a
camera-mount conversion method which is the easiest for those with a cabinet full of renegades (I'm still too lazy but will do this to my K100D).
The best resources for the conversions is surely the
alternative gear section of fredmiranda's and the
manualfocusforum.
Good starting point hopefully:
Other manual lenses >> PK
In the above-mentioned thread there is the link to a french thread which pictures the
abundance of lenses you can put on with the camera mount conversion
One more especially for
Oly to PK
Maybe the easiest is to grab your Nikon lenses and give them a try (the older the better the chances). These will either fit right onto PK or not.
Beware of anything that could trip in the screwholes or the AF-hole on the mount, Murphy's law is always in full effect :-)
Best, Georg (the other)