Is there a corn variety that produces 12 ears on 1 stalk?

Yes, it's the kind that Chinese "baby corn" like you see in restaurant salad bars or in stir-fry cooking comes from. This unique kind of corn can produce as many as 20 ears on a single stalk. However, they will never grow bigger than "baby" size. In the inland Pacific Northwest area of the US the stalks can reach as much as 20 feet tall to the tip of the tassel.

Chinese baby corn should not be confused with normal sweet corn which has simply been planted in very high populations, picked early, and called "baby corn". They are two different varieties, and produce a very different end product.