Thanks for the credit.
Have you tested it on products with options? For example, a product with sizes/color options? I did find out that my original changes work fine except with optioned products. They show up and it lets you "add to cart" but then they don't actually show up in the cart. I'm guessing something in cart.php needs to be changed but I haven't looked at it yet. For now, I'm just not using any product options in my store.