How do I separate the "Product" select list & "Add to cart" submit form in a node product display?
I realized that you can't, albeit after several hours of experimenting.

However, you can add a price field (and other fields) to your "add to cart" form by adding a "price" form item element. Follow the instructions here for more details: http://drupal.org/node/1300798#comment-5328550

Tell me if this helps.