I was wondering if their were any existing rules allowing for a character to attract a group of followers (be it for a thieves guild, mage tower, or the like) of classes related to, but not exactly the same as their own class. I have a couple of friends with demihuman characters living deep in human lands, far removed from their own kind. I figured it would be more likely for an exotic and powerful demihuman attracting local human followers than a group of low-level elves or dwarves traveling hundreds of miles through monster-infested lands out of the blue. So, could a high level Elven Nightblade be able to attract human thieves or assassins, resulting in the equivalent of a thief or assassin’s hideout?
I could see this being a house rule if not explicitly mentioned, I just wanted to see if it had come up in the past.
It's not explicitly handled in the rules, but I think what you are suggesting for your campaign is very reasonable and probably the right thing to do!
The only one I'd be cautious about is allowing someone to get clerical followers, as those are the best followers to get in terms of numbers and morale. I think you can freely and reasonable trade between mage, thief, and fighter followers without real issue. Doing so creates an interestingly different "feel" for the class. For example, if an explorer gets a hideout and thief followers, he feels like Robin Hood. A mage who gets fighter followers might feel like a sorerer-king.
I was actually thinking more along the lines of a closely related class (nightblade to assassin, spellsword to fighter, etc.), but having a very different set of followers is intriguing. My nightblade friend was always a bit unnerved about inviting a half dozen new magic-elf-assassins to live in his home. I can think of many times when a high-level adventurer might prefer followers that specialize in areas that he doesn’t.
To clarify, it actually isn’t really my campaign, I’m just a player, so it is up to the judge. I was just wondering hypothetically.