Hi Ben,
How small ( 8' high?) I built a nice little 8' coil but the
transformer I was using burnt out and as it was easier to buy a neon I built a
bigger better coil. The big advantage of little coils is that the caps can be
made easily or bought quite cheaply.
Finding suitably weedy transformers is hard. I got hold of the transformers
out of a pair of lab eht supplies and put the 3kV windings in series.
Nick Field