The Toxic Terror

I had a chat with a long, LONG timer Invulnerability Tanker who has expressed many times the "psionic hole" in his defenses, but nowadays with IOs, the hole is quite a bit smaller than it used to be. Toxic, though... that one's not so much an issue. Not because of the defenses, but because of rarity. I mean, how often do you encounter dedicated Toxic damage in the game?

I've been wondering... what combination of powers would give a character the absolute most in toxic output? From some cursory research, it'd seem to me that the best combination would be a specially-crafted Bane Spider Soldier. Venom Grenade, Poisonous Ray and Bile Spray are all high AoE Toxic damage, and all the Arachnos Mace attacks have a Toxic DoT on them. But is it enough to topple defensive characters?

What other options might there be? Is it at all worth it to craft a character especially for Toxic damage?

AFAIK, there are no un-positional Toxic attacks available to players.

As far as maximum Toxic damage goes, a Bane would be hard to beat a Necro/Traps/Mako MM (MMs get Bile Spray too).