> >
Would not a green & red Ne-2 would fit the mood better.> If you have = 
 the
HV why not go nixe tube?>=20
 There is no green Ne-2. You can put a filter on a NE-2 and
 get a nice red or yellow but not green. 
 
Maybe not strictly an NE2, but there are green and blue neons avaiable.
They have a phosphor coating on the inside of the glass, and I _think_
the gas inside is still neon (I see to remember seeing the classic orange
glow trhough the glass around the leadout wires).
-tony