you can get 4ws on 2500s and 3500s by chevy actually, and its even a better system then on the 1500.
There are SuperDuty's with the four wheel steering but they are not for sale /forums/images/graemlins/frown.gif Delphi Automotive (the developer of the 4ws) has an exclusive deal with GM products for two years. However, based on sales figures, Ford may ultimately decide to pass on it. Locally, sales are pretty poor even after the price cut from $4000 to $2000. Most vehicles that have it (locally) are PEP vehicles that are sold to GM employees for 28% off.
Now, about the SuperDuty so i can't be accused of "thread-jacking". I've had my V-10 SuperDuty since 1998 and have been extremely pleased with it. It has been overloaded, jumped (think 'Dukes of Hazzard' style), and extensively off-roaded and has held up very well. When it comes time for a new truck there is no question that it will be a SuperDuty, even though I have GM employee discounts and could get GM truck cheaper. The SuperDuty has a wider cab for more hiproom, a taller roof for more headroom, and better engines.
As far as diesel trucks being cheaper to operate than gassers, back when diesel was cheaper than gas the break point for the diesel to start saving money over the gasser was 100,000 miles. This takes into consideration fuel price and maintainance issues but not engine life.