Hey Mark,
I don't know if you've taken care of business on your end, but just in case, I recently moved away from missouri but still have information on hogs in the state. The populations are down significantly, though you can still find them on public land around Truman and Wapapello. Eric Lemon (Eric.G.Lemons@mvs02.usace.army.mil) is the Natural Resources Park Ranger for Wapapello and was happy to help. He gave me a map (I'm having trouble uploading the map, but will gladly email it to anybody wnating a copy) of where hogs have been seen in the recent past and offered to give me any updates on locations and activity if I call or email a couple weeks before coming his way.
At Truman, Danny Sandersfeld (Danny.L.Sandersfeld@nwk02.usace.army.mil) would be your point of contact. He's also a good guy who will do what he can to put you on some hogs. He doesn't have a map readily on hand but will mail one to you with some areas circled.
Anyways, I hope this is of use to you. I never got the chance to use the information, so I don't know how the hunting is in those areas currently. If you get out, though, be sure to let us know how it goes.