Did you guys see the method described in this instructable?
http://www.instructables.com/id/Sleek-word-clock/
It seems to be the simplest and cheapest (although not the (world) sleekest, as claimed).
That's pretty cool. I am considering trying etching through paint as I have tried before, maybe a with a few coats of black it willl block all the light and then with the paint inside (reversed text) it will be thinner than doing all acrylic layers. It would also allow you to do non-stencil lettering. I just need to find some ultra-black quick drying spray or even coat stuff to paint on.
If I get this sorted, anyone interested in one? At the moment I will just be making a case but I might get a pcb done depending on interest.
Pic of first test coming soon...
Mowcius