The code for this would not take very long to make, but you stand no chance of getting it included because of balance. To properly balance a new commodity takes hours of work, which I am beting the Dev team does not have very much to spare.
What you could do is pitch the idea of "roleplay" commodities. Basically all these are is an Icon, a handful of code and an info card. They would have a uniform buy/sell price and basically only exist for roleplaying.
