i think if u take out megingjard in the equation you'll probably reach around 700-900k
How to get Asura Strike 999,999 Damage against certain MVPS (http://www.youtube.com/watch?v=MLr_LIga798#ws)
Some of that gear is really old, it's much more easy to get that nowadays. Pretty much the trick for that in the video is called Gloom, megs, tanee and lex ...
And he could get more dmg since he's not using luna kaligo, proxy, evil wings, diabulos robe and shield cards.
He also gives dmg > 999999 since he one-shots the valk, the game has a cap on the display.