As I was poking around considering various possibilities for creating the pond surface, I found these nice wood slabs with the bark still attached at Jo-Ann's. They basically just cut diagonally across the log to make an oval, sanded the cut surfaces smooth, and left it at that.
I was looking at various other unfinished wood pieces, but when I saw this, I liked the natural look of having the bark on it. All it needed was a little paint. I may have to outsource the more complex painting projects, but even I can manage to cover a flat surface in a solid color.
I am in the process of finishing it with a clear protective varnish on both sides. It's taking more coats than I was expecting to get the nice smooth finish I want, but I think one more coat should do it. Then I'll be ready to start gluing down the tatting.