There are plenty of unique approaches to create a NFL mock draft. Drafttek has their own unique approach outlined below from their website.
“Drafttek.com uses a computer model to simulate a 7-round 2012 NFL Mock Draft. Each team has an analyst who supplies data on 2012 NFL Draft team needs. The team needs are matched up against a list of 2012 NFL Draft prospect rankings (aka "Big Board") in order to generate each selection in our 2012 NFL Mock Draft.”
Here is the link for Drafttek’s full seven-round mock draft.
There are no perfect mock drafts before or after the draft. Everyone has their own opinions and each team drafts based on opinions that no one outside of their organization knows. For the Dallas Cowboys, Jerry Jones’ opinion matters more than anyone but here is my opinion on Drafttek’s picks for the Cowboys.