There are a few ways to do this.

First a comment: For shopowners who use the products-description field to show detailed, colorful, lengthy details about their products, this would be a bad idea. You don't want a 1/2 screen of information coming up under each product ... you'd annoy more customers than you'd please.
However, in the case of your stamp store, you likely only need a small amount of information and likely rely more on images than text. Thus, perhaps the products-description content could be sufficient.

Possible approaches:
1. Use READONLY attributes to describe the components. This is ideal if there are common things that can be attributed to these products. It's not ideal for one-off details.

2. Add a custom field to the product which is editable in the admin area when entering/editing products, and is optionally displayed in the shop. It would be primarily used for displaying order details on invoice/packing-slip etc.
You would have to modify the order class to populate the orders_products.details field from the products_description.details field when the order is placed. The order class also sends the order-confirmation email, so would have to accomodate this as well. The invoice/packing-slip would need to pull the info for display too.

3. Build information into the products_name. However, this is by default limited to 100 characters. This may not produce the desired visual. You could override the long name using per-product-metatags settings and set an override title for the product for more pleasant title display in browser and search engines.

4. You could extend the orders_products.products_name field to much longer and then tell the order class to append the description to the name, up to a maximum of XX characters total. You'd need to do some special coding to handle the insertion of a suitable line-break character (emails vs browser issues) or other separator notation, and pull the description from the database (ie: zen_get products_description($products_id), etc).


I think #4 is likely the least overall work but may produce some odd results in reports, etc.