Sorry to tell you all this, but samurais are only men, so an assasin can't be a samurai,
Samurai-ko. Problem solved.

rop: Unless you're going to say that I'm just making up that, in which case I'll refer you to everything else in D2.
The biggest issue for me with Samurai builds is that Assassins are really pathetically slow with 2H swords unless you kick, which doesn't fit the theme. I've had a lot of fun with with them anyway, but it's really difficult. They look extremely cool at least.
One handed swords are quicker, and the Falchion type swords look pretty katana/wakizashi-like, but there aren't a lot of good weapon options there as the uniques are limited and they only have a 2 socket max. P
They're quite slow with spears too, so that doesn't help.
Polearms are much better on Assassins, and good looking too, though none of them look quite right for the theme.