What is the single highest instance of damage possible?

I recently got a critical hit of über-Karlach (a stupid build where I buff Karlach out the ass and then she just steamrolls everything) for a single instance of 230 damage. It got me thinking: what would be the highest single damage instance (one hit/number) you could achieve?

My personal theory (although I haven't found somewhere to test it yet) would be to stack a bunch of buffs and potions onto an assassin rogue's sneak attack, then find as many modifiers as possible yo amplify it (IE damage Amp on the target, maybe a racial damage increase, etc).

Any ideas for how to do more damage, or has anyone else gotten a higher hit?