Yesterday,
Alice suggested playing with the background on my
manipulated photo. So, I downloaded
GIMP, which is a free open-source drawing program with lots of advanced features. It's great. There's definitely a learning curve involved, but it's pretty easy to do what you want once you get beyond it. It's still not as flexible as I would want, but hey, it's free.
So, here's the same image with colors darkened and a striped background added. Removing the naturalistic ground definitely adds to the disembodied effect I'm going for. To that end, I had also removed the shadows from the wires but not the flat pieces. And I blurred the wires while sharpening the flat pieces. Little optical inconsistencies to enhance (subtly) the other-worldly feel.

Here is another composite photo made with GIMP. Again, three separate images of another mobile, but this time without flash and hence without shadows, which flattens the perspective and results in an op-art-like look. With GIMP, I also have much finer control over the opacity of each layer than with the word processor (Pages) I was using before.

Next: selectively including shadows in various parts of the composite. I want to try mixing the 2D and 3D qualities of these two images for a more disorienting effect.