[Zope] Class templates / meta classes

Hi I am building a fairly simple On-line Shopping Product (I know there some out there already, but please humour me) with a number of ZClasses. Different shop instances will obviously need to be customizeable, for example the properties available for items in a shop might be different from shop to shop. How can I use my generic Shop Product to make a different Product each time I deploy a new shop? I am sort of looking to make a meta-class. Does this make any sense to anyone? Felix.