I've gone ahead and built a model sized Gray's Tube,
as shown below in Pic 1 -

The alignment is not yet completely done, but its
fairly straight considering my extensive use of
rubbery silicone as the main structural element.

Below the 1st Pic is another showing an overview of
the total construction.

To explain briefly, the positive battery post is
wired through a large switch, once thrown will
power on the timing device I've made from a small
PC fan.

-----------------
The fan spins a series of magnets, which vibrate
a single magnet soldered onto a two-wire commutator
junction for supplying 12V into the Tube past a
30KV diode, which I might add drops it down to
a little over 1(one) Volt...  ?? Should this be
happening?
-----------------

A second switch turns on the 25KV high-frequency
power supply (previously a negative ion generator)
to be powered directly from the 12V battery.

In my video, once the switch is thrown on the battery, the fan
speeds up and begins commutating the 12V into the tube.  Then
the focus is moved right onto the tube while I turn on the
25KV power supply, and as can be seen it arcs onto the copper
mesh against the +12V and putters out my commutator.

<< Video Link >>

Its been a while in the making... I sure hope there's something
that can be fixed on it to get a proper sustainable effect.
I was thinking perhaps with using such a high-voltage potential
it might be that my copper mesh tubes are just too small a
diameter...

Once I find some thicker copper electrodes I'll be gently
rebuilding it with a bit more structural integrity.