So I've been thinking of doing this for a while, and then they gave orb of storms a 70% base damage buff.
My first attempt: https://pastebin.com/sYTBZbZD
Necromancer for attack speed on corpse consumption
Asenath's Chant gmp-lmp-unearth-spirit offering for corpses and tons of es regen
Elemental hit + no lightning to trigger Orb of storms procs and not deal any lighting for Elemental equilibrium
Thief's torment or poacher's mark for mana on hit
11 attacks a second, each firing a ~20k zap from the orb
also 9 zombies and 2 spectres.

That was my initial thought, anyway. Any other ideas?