I read somewhere that the Notoriety level cap for basic pirates was 12, with one exception, pirates that WERE unlimited, that have changed to basic status. In that case, they maintain thier Notoriety level I believe, but lose access to all unlimited access weapons. And the weapons, ships, etc they have are reverted back to the best Basic can allow. Pay unlimited again, get it all back.
Furthest I ever got questing on basic was up until I had to see Tia about the voodoo doll, and got prompted to upgrade (somewhere around lvl7 depending on wether your killing stuff or questing).
Zeppers Lvl38
http://pirates.teamofx.us