A Christian Berber-Hispanic state would probably be quite interesting - especially as it makes the routes not only to itself, but to Outremer more secure.
In fact, I'm not sure WHEN the Portuguese started to have an overpopulation problem (one of their motivations to expand overseas), but I could see loads of Portuguese settlers go to Tunis, simply because if it all goes wrong it is so much easier to get home.
Catholic Berber, Hispanic and Portuguese state in Tunisia could be a game changer - it cuts of the Maghreb from the east - but might end up being on the sour end of Venice. Trade west of Italy was typically the domain of Genoa - which would likely mean that Genoa gets a boost in its fortunes.
Man, the actors in that little state could be fun. Berbers, Portuguese, Genovese, Spanish, and of course, Cardinals and Franks. It also creates a source for light cavalry forces that Europe really didn't use at the time, that if supported and growing through conquest and conversion of the Maghreb could later go to support Jerusalem or Antioch, giving an actual counter to Arab light cavalry.
What was there to trade from the Maghreb at this point (and did Genoa partake?) because if funding mercenaries to assist the state leads to profits, Genoa might end up paying to send forces abroad, infesting the state economically.