I like your idea of using a new warehouse, it Looks like the best possible direction to start looking.
Let me reference your products in AX Terms:
Small Kits - AX Product
Item - AX BOM
Can you consider Production in AX?
If you can move the BOM to your new warehouse, and perform a Production function in AX (where in reality it is just packaging), you will get the produced Item, which you can move back to your warehouse.
If you like this approach, you can do it with 0 (or almost Nil) Customization