Here's how I think of products, attributes, and kits. Products are the actual things that are sold, so those are what you keep track of in inventory with SKU or model numbers. Some products are very similar, but their differences are described with attributes. Each different product has its own SKU. Product kits are simply groups of products. A kit itself won't have an SKU because you're already keeping track of the component products.

That's why I don't really like the idea of putting attributes on product kits. They aren't actual things that you change. The products inside them are. That said, I do like the idea of having one kit page, and having a choice of which products to get in it. It's a good idea, but the code that's already there would make it hard to do. I think.

This might be a good opportunity for a new module.