I did it when I was in college, only required one other class. If I remember the requirements were 200hrs of classroom time or two years 121 experience and the written test then you could take the practical. See if you can find a dispatch examiner (Check with your FSDO) then ask them. If you were at Comair two years you should be eligible. Take the written (exactly the same as the ATP written), study up on 121 and Comair's ops specs (if you still have a copy) and that's what the practical will cover. Like an ATP without the flight. If I remember there was also a flight planning requirement. Again, talk to your local FSDO.

Edit: It's Part 65.50. Two years within the last three years before the practical is the requirement.