Just a little update, I've tried regular neon indicator bulbs (most of them
start conduction at around 75V) and only one showed oscillations and
only at low max current ratings.
https://www.dropbox.com/s/padumhxip1...-neon.zip?dl=0

Here're a few pictures of the V/I traces of regular small lamps.
Tilted traces are lamps with internal resistor, so the resistor is
tilting the trace.
Frank