While not as ambitious as some of the projects outlined here, I've thought that the final scene from O. Henry's Jimmy Hayes and Muriel would make a wonderful diorama. It would involve at least five or six Texas Ranger figures (how many are in a "half troop"?) plus their mounts, tack, and weapons, 4 skeletonized figures, and a horned toad figure (Muriel). The cheering Rangers would allow for dynamic poses, some mounted, some not, and even the skeletonized remains of Jimmy Hayes and the bandits would have to be well posed to properly tell the story. And then there's Muriel...
The terrain would have to be large enough to tell the story properly, and the scale would have to be such that a scale horned toad would show up. Possibly 54mm would work, but 75mm or 90mm would be better. Allowing for artistic license, the scene could be done at a base size of around 4' x 2' in 54mm.
It's beyond my talent and time at present, but perhaps one day.