I'm pretty sure the MCG has already been done by JK. I'm really unsure as to how the quality of my stadium matches up with the stuff JK has done. Mine might be really crap or really good. If mine turns out to be better I would be more than happy to re-make other ones, and similarly if mine is worse, I'd be more than happy for someone to re-make mine.
I only really learned how to use Maya a few months ago for uni, and I'm learning all the time. For example, the pavilion I did first is really basic and may well need to be re-done with a bit more detail.
If anyone else is just starting out in 3D, then architectural models are a good way to begin because they're quite easy to model. So far I've only used poly cubes and a few planes to make my stands. It's just the placement, scale, rotation etc which makes them into a stadium.
I'd like to see some other people on here having a go at a stadium which hasn't been done. I'm sure some of you have the skills to put on display!