I believe that FedEx is planning to convert all DC-10 to the new MD-10 configuration. It saves money having crew members that can fly both the 10 and 11 and removes the need for the third fight deck member.
The cockpit modification will allow the cockpits to be the "same" for both aircraft thus new displays and software had to be developed by Honeywell since the DC-10 is an analog aircraft while the MD-11 is digital....Or so I am told (father works on conversion program for FedEx). The first flight tests of the cockpit conversion took place several months ago and I don't believe FedEx has begun the full process on converting the 10s yet. They are, however, in the process of converting the 10s and 11s purchased from UA and AA into cargo aircraft. I believe this is taking place in Tuscon and Mobile and I am not sure if the line is still open in Goodyear (Phoenix).
As far as when the new cockpit enters into full service, I am not sure. I'll see if I can find out though and post back here.