Hi Ham,
Maybe you can use a mapping table. product_id, color, price or something like that. Although you will have to join this additional table.
I guess if it will be done like this, the best long term way is have e-commerce accept attributes and stuff. Since its likely others will have a need to have price dictated by other attributes other than color. Which may take too much volunteer effort. It would be nice to if a project will require e-commerce to make use of CR. So product_id is actually item_id. Or something like that. Then this will be donated back to OpenACS.
Good luck, you can still reach me if you want to further discuss about this.
