F450 dually to 4WD conversion?

[RazzleFrazzle]

I have a 2000 F450, 7.3, 6-speed manual and was entertaining the idea of converting it to 4WD. Is it possible to do so without major modifications of the chassis or some other major issue? I have noticed that the front straight axle might lend itself to an easier than otherwise conversion. I also understand that we are talking about acquiring a transfer case, drive shafts, possible 6-speed housing modification, cross members and matching the front/back gearing. I am not a virgin at the mechanicing part of the project I was just wanting to get some input into what components I would be looking for and which ones I should avoid. I don't intend to tear into this thing blindly, I would like to get as much input as feasible. I suppose the ideal way to go would be to find a 2000 F450, dually, 7.3, 6-speed with a 4WD setup that might be wrecked, burned up or blown up and cannibalize the parts I need and part out the rest. This sounds like the most logical route and I would be completely open to this except for the fact that as I have searched for the past couple of months I can't seem to find such a setup. If anyone can direct me to such a source I would trully appreciate it or maybe direct me to a source for the required parts. I am located in the midwest, near St. Louis, so something in that region would be outstanding. Thank for taking the time to read this and much appreciate any input.