I saw on e-Bay someone looking for people to become a distributor of his plane kits/designs at a cost of $3500. When you go to his site, he has info on an King Air kit in development. I checked but he doesn't have a recent listing. You might check periodically. His ad states "R/C Pilots Wanted".

Check out this site of a scratch-build project.

http://www.nextcraft.com/b200_construction01.html