Ninja Scroll was an absolutely kickass anime.
A live action version of it would be cool if it was done right.. but things 'made into movies' from thier origional forms seldom turn out spectacular. Odds are they'd tone it down to suit a wider audience than just Otakus interested in seeing the live movie, and in all likelyhood some of the more out there characters would end up just being funky when translated into actual life (like the old government agent.. or the rock dude.. Sorry if I sound like a dumb@$$ but it's been a long time since I've seen Ninja Scroll)