I have a wallet similar to this one (but with card slots on both sides). It can be a bit tricky at times with Aussie notes as they tend to slide. If you get them in right the first time then you should be fine. If your taking cash out of the ATM at 3am and just stuff them in then you'll wake up to find notes sticking out everywhere.
Also you're right that you can't carry that much cash around either ...maybe about 10 to 12 notes before it starts looking a bit thick.
I've been looking at new wallets lately, and noticed quite a few with a money clip inside.
Has anyone got one of these? It strikes me that they wont work very well with Australian currency, which doesn't tend to stay folded as well as US dollars or pound notes.
I also worry its a bit tacky, even an invitation to theft if you're carrying a lot of cash...