So, I got some positive feedback (a little, anyway) and so I thought I'd try to do something practical with my new roofs. To go along with my The Garden - City Walls kitbash, I would like to add roof pieces. Here's the results of a few minutes of tinkering in GIMP:
Right now, it's a very repetitive pattern, but that's the idea - wooden shingles that kinda look like leaves. I think I can make a quick brush out of something like that, add some jitter to it, play around with staining the pieces a little, and voila!
I had wanted to make some houses that blended with trees a bit, and this would serve as a good roof system for those, too.