Hi
You have a lot of choices in Zen Cart. You can use diferent products for each catagory or you could use one product with one or more atribute catagories. You could even place a unordered list of the product numbers as part of the product info that brings up a pop-up window and have one set of atributes that show each model number and set the price to _X for each for each atribute.
You can check out my store at
http://www.london-directory.biz/store the flower section shows multiple atribute catagories.
Kind regards
Stephan Toth