If it's 3D, I fear it'll try to be Ninja Gaiden Black, and I don't think the DS will do it very well. They are welcome to prove me wrong. I was exaggerating in my post, but I'd much prefer a 2D ninja gaiden.
Ninja Gaiden Dragon Sword could be pretty awesome if it's not 3D.
It's laughable to think you could even port Ninja Gaiden to the DS from the XBox... it's going to be a completely new engine and game. I guess they could "remake" part of Ninja Gaiden for Xbox on it, but that'd be pretty much pointless.
Not remakes, necessarily, but what about a "New Ninja Gaiden" type of thing?
3D Ninja Gaiden fans are already going to get what they want through NG2 for the 360 and Sigma for the PS3. As long as the DS is going to be the one that is perhaps the most amiable environment for a 2D/"2D style" game, they should make it so that we can have a new, polygon-employing side-scroller that marries the best attributes of the old school and the new school NG games. Again, not unlike what NSMB seemed to be about.