Just bought a 2010 MKZ and am really happy with it - spent some time yesterday trying to get the factory code for the keypad so I can set a personal code, but since I am not the first owner and don't have the wallet card, I couldn't get started. Called my local Lincoln dealer and they said - "Sure - bring the car and $60 dollars in and we'll retrieve it for you". Not thrilled with that response I looked around the internet and found the answer in the Mercury Milan forum. Get an extendable inspection mirror from your local hardware store for a few bucks and extend it up under the dashboard just to the left of the steering wheel. Next to and slightly above the fuse box there are a bunch of modules but only one will have a 5-digit number on a white sticker. You need the mirror to read it, but with the mirror it took me less than 30 seconds.
Also - the printed documentation for setting the personal codes leaves out one critical step. You to have the key in the ignition to set a personal code (I left the sunroof open during the process just in case I locked it by mistake). Once I did that the process went as advertised. Hope this helps someone out there and saves them the $50-60 that the unhelpful dealers wanted.