I like the idea of an austrailian sub-group. I agree that it should be based highly in bretonian lore.
A while back, I had an idea for a similar thing to this, but they were Zoners, and they were lawful bretonian. Essentially, they were Breotnian explorers and colonists, living on the fringe of bretonian space, and balanced the tenitive link between Bretonia and the Zoners. I liked the idea, mainly because they didn't (in my opinion) recycle the story of "oppressed minority living on the edges of space rebels against its house." I called them the Outbackers, and although I never actually made the player group, I had a lot of fun RPing my character as one of the members of this sub-culture. If you want to talk about this, my skype is azraeles27 . The whole idea of Bretonian frontiersmen was incredibly fun, and I hope you can capture the spirit of this in your faction.
Also, I would suggest shying away from any sort of racial barrier between you and Bretonia. Cultural, philosphical, or social, sure, but not racial. Even the vanilla mollys (who were blaitently Irish) were deviod of any canon racial conflict with Bretonia. Nowadays, thats changed, but in my opinion, almost none of the conflicts in vanilla were based on earth-like racial predudace, but instead on fresh ideological diffrences that brought about memorys of earth conflicts.
