can you use photoshop???
take a picture you wanna use, then add a new layer and have it completly white. the new layer is no on top of the picture so you only see a white layer.
take the capasity to 40-60% on the white layer then you now can see the pic becuase the white layer is transperant.
perss U on your key board and you get a new tool bar at the top sett the first option to fil pixels and the second one to line tool and the 3. to 1 or 2 pixels (upp to you how you wannt it) 4. normal and 5. at 100%
now you just zoom inn a lot and draw the lines of the car when you done you take the white layer to 100% capasity and yuou will see a with background with the lines you drawd on (the car) ^^
im a newb to photoshop but i understand pretty much what you meant ... so using like pen or pencil tool to trace the outline of car is the best, proper, and only way to do cartooning ?