The second Brisbane team, presumably south Bris, could easily be hosted at the UQ grounds which fits at least 1500 in the stands. it is only a 5 minute walk across the bridge at yeronga, which is the closest quality stadium to the south side.
It's not an enclosed ground though, so they'd lose a fair bit from ticketing sales.
Brothers set-up is good for watching the footy (the hill and the clubhouse bit), but it is a dump right now. The fields are shocking and the facilities are pretty poor.
Sunnybank, Easts, GPS, Wests, Souths and Norths are just standard suburban fields and don't have the necessary facilities.
Jets Langlands park suggestion was a good one, that was the first ground that came to my mind, but obviously wouldn't work.
Maybe we should be getting onto one of the Schools about it
Marist Ashgrove could hold a few, and Villa Park is one of the best schoolboy grounds in Brisbane (you can tell I'm an Old Boy!).
All fantasy thoughts, the only viable option is for both teams to play out of Ballymore. I for one would happily watch double-headers there every second weekend or so.