And in addition to all the places I mentioned, I missed the most obvious one ... the one we use most often for our hub-and-spoke tours:

Cabins in the caravan parks.

Here in Australia caravan parks contain a designated area for tent camping, an area for caravans, often some fixed caravans which they might rent out (although those are getting rarer), and a set of cabins of various sizes.

We usually stay in a smallish cabin.

Big 4, for example, is one of the biggest chains ... although you'll often find better prices (and more tent camping selection) at some of the smaller non-chain caravan parks. However, it's a good example of an Australian caravan park:
http://www.big4.com.au/

From that main site, let's grab Victoria Holiday Accommodations and Apollo Bay (a nice beach town along the Great Ocean Road)
http://pisces-holiday-park.vic.big4.com.au/

If you click Cabins, you'll see you can get various levels of luxury. And as soon as the summer holiday season is over (early February), the price for the Ensuite Cabin (the most basic one they've got), drops to $85/night, which is quite reasonable.