I'd love to see a mod of some sort that has a live trading system, goods that are abundant and cheap in Leyawin (fish or a certain herb etc) might be worth tons in Bruma and vice versa. Being able to perhaps join trading syndicates in a similar way to investing in shops? Perhaps being able to raid these wagons as well if you want the highwayman style of character?
I'd love to see somethign like this if it exists, even if it's a simple and small version.