I am wiring lights to several locomotives & am wondering if any railroads mount ditch lights on the rear of the engine for reverse running.
In short, Yes. There are a few roads that have done it. For example, BNSF has several GP units equipped with them on both ends.
That is very common if they are used as switchers.
More decoders are going to be made with more function outputs so that we can model this as well. I believe teh new QSI sound decoders will have up to 10 functions.