| Sean Mahoney |
I believe so.
Paizo has said they were introducing archetypes for new classes in the same book that they come out in so that they feel as supported as the previous classes (so gunslinger got archetypes in UC). Ninja and Samurai, however, did not. I believe this is because they are alternate classes and can take archetypes of those classes if they have the abilities to qualify.
That being the case, it would mean that the Ninja can take any of 5 rogue archetypes: Bandit, Burglar, Sanctified Rogue, Scout and Trapsmith.
[cheap plug]
For more Ninja fun listen to the upcoming episode #4 of The Gamers' Guide to Pathfinder podcast which deals with adding the eastern flavored elements of UC to your game. It covers, eastern armor and weapons, as well as the Samurai and Ninja in depth. It should be up by the end of the week! (still editing)
The Gamers' Guide to Pathfinder
[/cheap plug]
Sean