I would be happy if any teams came over here to play. From a personal (biased!) point of view, I would love for my Knights to come over here for a game. There are plenty of us Novocastrians here in Perth...!
Did Brett Kimmorley really say it was a waste of time playing over here? This just gives me one more reason to hate the useless hack.
I don't believe Melbourne would be the best idea. When the WARL were trying to entice clubs to play over here a few years ago, one WARL board member said in my prescence that Melbourne attracted the least interest of all the clubs at the time (this was in about 2004 he said this). This may have changed since, with Melbourne being the highly successful team that they have since become.
I would suggest that Gold Coast would probably be the least supported NRL team in WA, given they're only in their 2nd season. That being said, I have seen a few people wearing Titans shorts, jerseys, etc, around the place.