I've just started into this in my spare time in a joint venture with my brother-in-law.
The Nautilus pictured below is about 30" long, and is carved into a sheet of 1/2" thick glass. It's NOT etched, but actually CARVED into the plate with a special blaster, and is fully three dimensional.
When the light hits it from the edges of the glass, the effect is astounding. You may have seen the same thing in some restaurants or other commercial businesses.
I need a bigger sheet of glass so I can do up a 7' long version, with all the rivetheads and window bezels shown