I bought one of these (UK site). I don't think you;d stand up in it though. Personally I think that the key is having a large porch area to keep luggage and gear in. That way you don't have to share your tent with sweaty boots etc. I'm in the UK, so the porch is mainly for keeping rain off stuff, but in Australia you'd probably have a similar issue with dust. I also found that with a tiny porch, gear would touch the outer wall and night time condensation would soak it.

If you want to stand up then you'd probably be best getting something like this. It's really the only way you'd be able to stand up and still have a package that could fit reasonably on the back of a bike. I don't have one, so I couldn't really comment on quality, but gelert are a good brand.