What exactly stops you from having more then 5 NPC

I'm presuming that if it was even remotely possible to screw around with the engine so that you could get more then 5 Npc's to join, someone would have made it by now...

But what exactly prevents you from doing so?

Are there any workarounds? At least such that are better then mass-domination?

Please, refer to the Frequently Occuring Ideas Thread. It has the link to the discussion of this particular topic. Also, the form sometimes give the "mail error" after you post - please, check if you indeed did not post. Igf you do not mind, I'll delete the duplicate entry of your question