What Av8r said. I only think this would be justified if you wanted to convert a crew cab. Otherwise you'd be better off if you just bought a 4wd truck, and have both. Same as auto to manual trans conversions. To answer your questions. 1)No on the 205. Diesel, auto, getrag versions. 2)I'm gonna say no, just from what I've read, I'm sure if you had all the money in the world you could do anything though. 3) you can find these parts every now and then in the tdr classifieds.
W models are ok, but I have 2 of them, and would like to have a nice club cab 5 speed 2wd D250. Don't use the 4wd hardly at all, so a nice 2wd would suit me better, better fuel mileage etc.