How can I generate a list of missing parts for incomplete sets?
Rebrickable.com offers this service. First add the complete set to you list, then view it on the set page like this http://rebrickable.com/sets/42029-1/customized-pick-up-truck-technic-2014 At the bottom of the first panel you'll have an option to "Add to my parts list" from then you go through the list of parts and remove the ones you are missing.