Well, if you want to bang your head a little harder, have you considered using a rotary encoder instead of a pot? Then you don't have to worry about linearity, ADC, pot reaching end of travel, etc.

Count the pulses going, and then back. Something like these:

http://www.ebay.ca/itm/ws/eBayISAPI....m=380410565135



I have yet to use one of these so I can't comment on their downsides. My order should get here any day.

Robert