This module allows you to group Ubercart attribute dropdown options into categories.
After installation, when adding or editing an attribute option a new "Act as category" checkbox will be available. Checking this will convert the option to a category, which will make it no longer selectable as a product option. All options listed immediately below a category will be displayed underneath the category heading in the dropdown attribute list. You can rearrange options and their categories as desired on the standard configuration pages.
Development sponsored by Big Concept Designs.