Ok, so I take the Swordsage, right? And I hand him some of that +P Alchemists' Fire from, like the Complete Adventurer that deals 2d6 fire damage, right? And I stick him in Assassin's Stance with Craven thrown in, right?
That's like 4d6+12 fire damage, right? So, what you could like totally do is get the drop on the dragon with Dalkstalker, and throw a bit of 4d6+12 splash damage goodness at his sorry touch AC, then on your round give him a bit of 4d6+12 lovin' and then WRT yourself another turn to give him one more dose of 4d6+12.
He'll then get upset and attack you, but you've got Concealment from your Smoking Weapon, so you'll probably survive the first round - or you could use a bit of teleportation to escape. Any ways, he's taken 12d6+36 fire damage, average of 78 fire damage. 156 points after factoring in a white dragon's vulnerability to fire.
During your melee attacks on him, you can get Burning blade which deals [W]+1d6+12 fire damage (Good with Emerald Razor), Burning Brand which turns melee damage into fire damage (Great with Ruby Nightmare Blade), and other options for setting him on fire.
Is there a flaw in my cunning plan?