Is there a forensic toxilcologist in the house...

[hanszurcher]

...
What about other methods of delivery; Inhalation, Contact and Ingestion?

I haven't dealt with poisons in Legend yet. But I generally only allow fast acting poisons if they are irritants ...powders or smokes that can be blown into an opponents face or inhaled. The sort of thing you'd use to gain an immediate edge in combat...causing skill penalties, temporary blindness, etc.

Asphyxiants can be pretty useful. The Spartans set fire to noxious substances under the walls of the Athenians.

Blades coated in anti-coagulants can be a fast acting and ugly way to gain an advantage.

I'd think most poisons in a fantasy game that required immediate onset sould be both rare and magical in nature.