The Sdp40 was one of Athearn's older style "wide hood" engines designed when Athearn's motor was too wide to fit inside a scale width shell. Since Athearn bought Railpower Products and thus aquired a bunch tooling for scale width shells, they have pretty much quit making any of their old locomotives with the wide shell. I think if you get a Sd40-2 model, and a Dd40x body, and cut the "v" shaped long hood end off the Sd40-2, and graft on an appropriate length of long hood with the squared off end of the Dd40x, you could probably kit bash a Sdp40. Undecorated Athearn bodies are only about $6.00 each retail, and frequently you can find damaged bodies at swap meet tables or at train shopw very cheap. Also for the Dd40x body, Bachmann made some Dd40x's with pancake motors that are virtually worthless now. You might be able to find some of those cheap. Also Lifelike, Model Power, or Bachmann made an inexpensive Sd40-2 with pancake motor years ago which are also pretty much worthless now. If you got those models from a swap meet you should be able to get all of the bodies you would need for the kitbash for $5-$6. You haven't risked anything trying a kitbash, and if it is successful, you could power it up with an Athearn chassis.