If you haven't visited this website, it's definitely worth visiting. If you scroll down to the bottom of the page and click the underlined blue link that says Delta Seat Mapper it takes you to a page where you can view the real-time updated seating layouts for any flight. All you need is to provide the flight number, date, orgin and destination, and whether it's a domestic or int'l config and the site displays the seating availablity of both classes. It's great for determining upgrade probability and checking what seats open up before your flight without having to navigate through all those pages on delta.com. It's definitely been a real convenient tool for me.

Give it a try!
www.upgradetracker.com
dlseats.statusrun.com (direct link to the seat mapper)