You can buy your own Priscilla!
I happened to be looking at the Australian Greyhound website and I spotted a tab at the top of the screen that said "Bus Sales." I thought, no, they can't mean actual buses for sale?! But oh, they do. You can buy your very own used coach for about $44,000 - that's only about 26,000 euros! O and I should totally buy one for when we travel in Australia. We'd just need a few buckets of lavender paint and Guy Pierce on the roof in a silver outfit and we'd be set.
Barring that, I am totally doing this type of trip when we are there. Besides being in Sydney for New Year's, this is the only other plan I've really had for what I absolutely must do in Australia. Arg, I can't wait...