Charlie, I too am enjoying your posts. I chuckle to myself when I see an idea that I too have thought of, and get inspired when I see an idea I hadn't considered.
For example, I too have modified the short stock car, only I used a K-Line 5000 series one. It was work to neatly cut out every other plank as you might also agree. Did the same thing, with the inserts from the O gauge longer Lionel poultry dispatch. Only I added a chicken figure from the movie, Chicken Run, in the open door.
I like the mini-aquarium and the idea for the "modern" tops for the hoppers. With prices being soft on used stuff, I have determined it is more profitable to scrap cars than to sell them for less than you can buy the parts. Check out the parts prices of wheel sets and trucks and you'll see what I mean. I've been using the cut roofs from box cars to make covers for hoppers and gondolas.
I've got to get around to figuring out my digital camera and do some photos of some of my creations. There are more of us 027 / traditional operators out there, than reading this particular forum category would give the appearance of.
Thanks for posting.