I am thinking strongly in favor of using kraft cardstock for the business cards. It is an artisan company using the best, all natural ingredients, and it's cornbread, so I think the kraft is a great way to convey the down-home nature of the product.
I don't want it too conventional! On the other hand, nothing from left field. This is a company that prides itself in not taking itself too seriously.
I also think having rounded corners would look really nice. I'm thinking all four corners, but I've also seen only two corners, and it's nice as well.
As for font, I want something unassuming and not to elitist looking. Maybe even courier would work, since it's kraft cardstock.
As for the back, I'm not sure what can go on there - this is where I will let the creative juices flow for everyone. Maybe a corn cob, maybe the tagline (again?), maybe something else. Your free reign here.