Can I assign an item number to an attribute?

I sell yarn and currently have to have a separate listing for every single color of yarn because I need to type in the item number to check people out in my store. (Our shopping cart works as our POS so we don't have to maintain separate inventories.)

My website would be a lot prettier if I could list one kind of yarn with all the color choices as attributes. Is this possible?

Have you considered http://www.zen-cart.com/index.php?main_page=product_contrib_info&products_id=1199

I have the older version of that (I know.. upgrade). But I don't see anywhere in the description that it will allow me to assign an item number to each attribute? (ie: yarn in color blue would be item number 403, green would be 404, orange would be 405, etc.)

Not in Zencart 1.3.9a, nor is there a mod I know of. Coming in version 2.0, I think.