Somewhere, online, I ran across a reproduction of an
entire booklet
on neon-bulb applications. I'll see if I can remember where...
There's a book called 'Cold Cathode Tube Circuit Design' which covers
all sorts of applications of these devices (and stabiliser valves, nixie
tubes, dekatrons etc). I certailly rememebr a neon shift register and
various logic gates.
-tony