Ok, so some of you are up for it by the sound of things - good!
I like the idea of going for a dagger & sword for anyone first. Could be used in all sorts of ways.
So, how about a soldier with a dagger, and a sword too. Make the anims work properly (ie., no gun anims!), and the damage appropriate to the weapon. Walk up, stab/slash, arrrggghh!
Next, add robes Mouldiwan Kenobi style, and you're onto a winner. Seat them in a tea garden and start an argument and you've got ancient Japan!
Then, a few different coloured robes, some women in robes, and perhaps either in armour of some kind, though no need to go over the top. Add some wooden huts, etc., a few objects like mats, bottles, redo the grenades to suit, and it's essentially there.
I'll outline something better when I'm awake tomorrow - past my bedtime here right now.

Edit:
As to the Xbox Ninja Gaiden thing - OFP is SO much more realistic and fun.
Picture yourself walk through a wood, out into a clearing, to face the one you
know just might cut you up bad, but you can't turn your back on this fight. A home-made smoke bomb may confuse, but this is a face to face job...