Add functionality to provide options to be based on custom field value OR stock field value.

Hello! Preface: I'm not a programmer, which is why I'm submitting a feature request. If I were a competent PHP man I'd write a module myself. That said, I'm willing to pay a reasonable bounty on this :) So do contact me if you're interested Mr. Maintainer!

I am working on a Commerce installation which requires the functionality to be able to alter the price of a product in the cart based on not quantity, but United Inches. This module would be PERFECT for this use case, if it had the option to alter the price table based on a custom field, instead of (or in addition to) the Quantity field.

Example: A Price Table reading from a custom field (Using the Commerce Product Option [http://drupal.org/project/commerce_option] & Attributes [http://drupal.org/project/commerce_product_attributes] module) could dictate price based on a user input value at the time of checkout. I.e. 10-20 United Inches is $5 per United Inch, while 21-30 United Inches is $4 per United Inch, etc., instead of basing the table on Quantity.

This would be a valuable feature in a number of custom applications.

EDIT: Title should read "Quantity" instead of "Stock", not sure what I was thinking when I wrote that!