Two questions.
The practical: Are there any books with ninja archetypes available? Preferably ones that are legal for PFS play, but for curiosity's sake, I'm curious about any.
The theoretical: Why aren't there any ninja/samurai archetypes in UC? It seems like a weird oversight, since there are several for gunslinger.
Is that in a piece of FAQ or errata? I'm looking for official information; I mostly play PFS.
I don't have such a link to answer your question, but this should be a start since it explains that they're more or less just really big archetypes, so you should be able to stack archetypes as long as you have the features to replace.
However, I would point out that there are also alternate class specific archetypes availible already, the Sword Saint for Samurai as an example. Point is, they don't have any right now... that doesn't mean they won't have a ninja specific one eventually.
Is that in a piece of FAQ or errata? I'm looking for official information; I mostly play PFS.
the Ninja is a fully statted out Rogue Archetype. Any Rogue class features that were not swapped out by the Ninja Archetype are usable with the Ninja.
I think Scout or Bandit works with it, my memory is fuzzy though.
Patrick, here are the sources.
http://paizo.com/forums/dmtz3e26?Samurai-First-impressions#22
http://paizo.com/forums/dmtz3e77&page=2?Alternate-class-what-I-dont-get -it#58