Sounds like something I can live without. Ausgamers is the only forum I check on my phone, hell it's pretty much the only forum I read, full stop.
Can't really speak for the technical feasibility, but I can say that it's not going to happen unless there's some way to retain advertising. Ads are the only thing that keep this place running and free to use.
charge people 10bux to register :p
But for serious, why not run a service where people can buy banner time? Say I wanted to advertise my knitting skills and knit the world a hat, I could pay to put a banner up advertising as such. Or would that kind of step on the toes of the professional advertisers & sponsors? I'm sure all the small business sparkies, mechanics, IT gurus, garden gnome polishers on here would probably love a week's worth of banner time.