How to create product sub-types

We have products of various types. They are each unique - think antiques - even if they have the same description - they are unique due to condition. Since my products cross many categories, I am trying to create a set of custom fields for each unique product type. for instance a "coin" would have some custom fields related to a "note", however, there would be different names and values associated with each type. Categorically speaking, different categories of coins have different sets of custom fields allowed in their descriptions. In non-wordpress nomenclature: I would like to make templates to add products to my site. If I choose to add a category (A) coin it will have different properties then a category(B) coin. A note will have different properties than a coin. All will have a few things in common: a unique barcode, product number, price based on formula, photo gallery, physical location. So all products must inherit general product related properties - and specific properties according to their "type". Help please.