If the rules of real life are true in EVE regarding social hiearchy (and I do not see why they wouldn't be), then at most 25 people should be in one organisation to avoid efficency loss and unwanted schisms withing the organisation (which is why for example modern armies try to make sure platoons are not larger than 25 men; it is the maximum number where people still work efficiently together without somebody taking a slack, while also being about the maximum number where people still feel "us vs them" which further tightens the social ties; same goes in schools too btw, it's been proven in various studies 24 students is the maximum number for efficient learning).
Let's call this organisation "corporation" and I think it might be something worth thinking at. Then again, a given corporation could have different divisions, where the maximum number of people are 25 per division at most. But that might be something for alliances, ie several corporations each with ~25 people each. OTOH, in EVE all players are not as active as everybody else, so most likely a slightly larger number of people might be possible to be handled without internal schisms etc.
Hmmm... EVE and MMO's in general would be such lovely things to test out various social and socio-economical theories
