Just to make sure I didn't screw up the front, I tried acid etching the back of one of the enclosures. I made a few mistakes (the toner didn't transfer entirely which botched the text) but otherwise it looks great. I think it will work out fine for the top as long the toner transfer goes well.
The etchant behaves a lot differently with aluminum. It doesn't require very much of the solution to get the reaction going, I'll use less next time and leave it for longer to get a deeper etch. I tested a few different resists (lacquer, sharpie, black acrylic paint, and the laser toner) and they all worked very well. I plan to take pictures of the process next time when I have a lovely (Kathy or Zack) assistant to help.
Anyway, here are some pictures:
And my favorite: