Probably not what you meant but Mo. Wildflower Nursery sells some seeds.

Here is a link that might be useful: MO Wildflowers

Have you asked Baker Creek where they get their seeds? That company has grown so huge. Surely they don't grow all their own seed. They must have some local suppliers.

This one is in Hartville Missouri
http://whiteharvestseed.com/

This one in Bolivar Missouri
http://www.grannysheirloomseeds.com/

It's hard to tell from websites whether they are producing their own seed or ordering from another supplier. Guess you'd just have to ask.