Here is a high quality 100kohm pot we have used before:
http://www.digikey.com/scripts/DkSea...423225&Site=US
They arn't cheap, but its practically impossible to break the stops on them. That particular model is the long shaft version, they are also avilable in a short shaft version (but its far easier to shorten a shaft than lengthen a shaft, so we usually buy long shaft versions and cut them down to whatever we need).