I don't want to belittle you like the two previous posters did, but I'm not sure where the challenge is. How is building this diesel any more of a challenge than building any other diesel locomotive. It's obvious from your post that this really isn't as much 'a challenge' as it is a 'build this for me' request.
It may have been recieved better if the request had been more carefully worded; however, I'm afraid that you might be in for some rather pointed posts as it comes across as a 'gimme' post.
I don't create diesels (and I only create for TRS2004), so I wouldn't be interested in it, but there might be someone willing to do it if it's a loco that there would be a demand for. If it's a loco that there wouldn't be a lot of demand for, your best bet would probably be commissioning someone to build it for you, but be prepared, that'll cost you. Your next best bet is to learn Gmax or Blender and build it yourself. Be forwarned though, I would never recommend that a loco (especially steam) be someone's initiatory experience in content creation.
As I said, maybe someone will come along who's willing to do it for you, but I would recommend being humble in your request.
Best of luck in your quest
Mike