Oh, FYI, there are classification lights children in Mr. Cowen's RS xtra series, and winterization hatches in two heights and a great GP series snowplow(plough) as children in his GP9 xtra set. Other nice detail items abound, like nose lifting rings, nose ladders, and other things in his FT-F3-F7-F9 sets. I imagine it wouldn't take a lot of asking to be able to get permission to use them.
I also have it on good authority that there will be several types of boxcar doors and roof walks as children soon.
