The closest subforum that I could think of was this one. It's not exactly a vehicle repaint, but it somewhat resembles a gameplay change.
I was somewhat disappointed at the very European-style icons for vehicles, so I decided I would 'Americanize' them. This mod changes the icons displayed above vehicles and stations, as well as relevant UI icons for train stations, train depots, and the list of vehicles. Please note: red outlines are not included in the mod.
For those who are curious, the icons are based off of the following:
Diesel locomotive: EMD F-unit
Electric locomotive: loosely based on a T-3 electric (NYC boxcab)
Truck: pickup truck with box
Trolley: generic bi-directional trolley
Passenger station: common road sign
Freight station: modification of the passenger station