Deer patch - I "talked" to Mo. He suggested you contact MFA Ag Services in Bethany, MO. He said he got some RR corn from them for less than $100 a bag. I would suspect you can find a Farm Co-op even closer, as the one he mentioned is north of KC on I-35.
I personally think the Rural king stuff will work fine and "SHOULD" be suited for your area. Like I said - that is where a local cooperative would be more helpful to ensure you get the proper maturity type and suggested planting dates and the like to fit your needs/wants.
See if this link helps you any. I think you are specifically interested in pages 45 thru 50.
http://www.rd.usda.gov/files/DirectoryOfFarmerCooperatives.pdf
You can also contact your local FSA office and they should be able to point you in the right direction as well.
http://offices.sc.egov.usda.gov/locator/app?state=ar&agency=fsa