Paladin 5/Kensai 10/Shing Blade 5?
For most amount of hurty on a sword.
No good, Paladin 10/Kensai 10 gains far better casting and some class abilities, and all it loses is a couple times per day you can burn a standard action to get a slight bonus. I'd actually put the one with more paladin as a better build.
@Strat: that's a good point, but what 6 level PrCs are there? Also, the point was made that by making it a Zhent fighter, the build becomes better.
@Akal: Again, more Paladin would be stronger. Yes, the Druid is nice, but that doesn't change the fact that Shining Blade isn't helping you there.
@Carnivore: Wouldn't the same build with less Shining Blade and more Contemplative get its abilities far quicker? Also, TWF and the Shining blade abilities don't synergize very well. I think your build would be greatly improved by this: Ranger 2 (Trapfinding)/Fighter 4/Paladin 4/Divine Crusader 3/Contemplative 7... so it doesn't work.
@Nox: You know, that's gaming the challenge a little, but it does look like a winner. We'll see if anyone can do better, but your use of a dead level to get it was quite creative. Next round of the challenge, I think I'll require that it be better both this level and next level, in the case of less than 20 level builds. But good job!
JaronK