Modify Allow Checkout

[jimmie]

if a customer orders 5 of something i have 3 in stock of.
if a customer orders in-stock and non-stock
Show a checkbox with this
You are ordering more quantity than in stock Please choose from an option below:
1. Complete Shipping - Your order will ship all items from our warehouse in 7-14 business days
2. DropShipping - All Stock and NON-Stock orders will ship all from our Distributors in 1-3 Business days
3. Partial Shipping - Stock items will ship from our warehouse in 1-3 business and Non-Stock items will ship from our warehouse in 7 - 14 business days
based on their choice, turn off other module(s) and show only that apply
jimmie

[mc12345678]

if a customer orders 5 of something i have 3 in stock of.
if a customer orders in-stock and non-stock
Show a checkbox with this
You are ordering more quantity than in stock Please choose from an option below:
1. Complete Shipping - Your order will ship all items from our warehouse in 7-14 business days
2. DropShipping - All Stock and NON-Stock orders will ship all from our Distributors in 1-3 Business days
3. Partial Shipping - Stock items will ship from our warehouse in 1-3 business and Non-Stock items will ship from our warehouse in 7 - 14 business days
based on their choice, turn off other module(s) and show only that apply
jimmie

If you're trying to tackle this as soon as items are being added to the cart, then would suggest using code in a new extra_cart_actions file... Set the result of the checkboxes to some session data related to the cart or shipping and use it later when the shipping module is calculating.