I made a long skinny one sided PCB today with the help of the glowforge. The board was only 1/2" wide but 10" long. I covered the copper clad board with Kapton tape, placed it in the GF, did a really light cut thru the tape and then weeded it where I wanted it to etch. Here is one being etched.
I am prototyping an ultra thin durable light panel to be used on stage, This one is using lights i had, They are 2812 chips, RGB and each one is addressable. This panel is 16x16 leds, I used the fastLED library for arduino and just used one of there demos. It draws nearly 150 watts.
I know this post is from long ago, but I just happened across it. Very cool Tom, making the masking for etching like that. And being able to solder it up with no wires from strip to strip, excellent! Have you experimented any further with PCB masking involving the GF?