Spigot,
There are many "if's and but's" with the FAA system, so the best thing to do would be to take the trip to the FSDO or contact Oklahoma in person. To MY knowledge, you would have to write the Part 121 ATP written and attend a full type rating course. (approved by the FAA) which would consist of a checkride covering both the MD 11 aswell as the ATP. This is for them to ensure that you can not only fly the machine (which you obviously can) but that you are knowledgable about the U.S. Federal aviation system.
Again this is just my opinion as an FAA rated instructor.
Good Luck