An XML spread sheet could be made in a folder, let's call it New_Products, and within this folder you can have the Images folder containing custom images. An entry in the XML could look like the following, though a programmer with inner working knowledge could certainly do a better job:
Rather than exporting the entire game's product-line to the XML, this would only be additions. It could be limited to a specific number of entries allowed if needed for any reason (like, say, 100), but this could be unlimited providing the game can handle it. The game on world creation could check for any resources listed until it reaches a command telling it to stop.
I imagine the game already breaks down production and other UI displays to what resources are needed to make a product (1, 2, or 3 different objects), so telling it to use blank sheet 1,2, or 3 and overlay info from the XML sheet using Y font, etc etc shouldn't be too bad...if that's how it works.
I'm not sure on how feasible this is for the game, since I really never took a look at the inner workings of it. Most of it is probably encrypted anyway. However, a method for "user modding" could help reinvigorate the game, add diversity, and expand game play with minimal effort and expense on the part of the game designer/programmer. This one addiction can provide a lot more content to users with less work needed by the game designer. So, I hope maybe this might receive some consideration.
Of course, XML isn't the only option. I've seen other game designers use .txt files and regular users are able to navigate and mod the game files just fine.
Thank you for your time and, I must say, I'm already looking forward to the add-on ever since finding out about it!
I tried running a search, but this specific suggestion didn't come up. Sorry if it's been mentioned before.