Far be it from me to try and talk somebody out of a jolly to Oz, a friend of mine has just flown a microlight all the way around it, and seems to have had a wonderful time.
But, I do think that potentially the cheapest way to gain hours is to buy a cheap PFA single seater and fly the pants off it. Let's say you want 500 hrs....
500hrs x cheap rental (£50/hr) = £25k
+ £1000 or so to get there and back, and miscellaneous expenses.
= £26k
Lets say you buy a minimax at about £5k.
500hrs x £20/hr = £10k
Sell it desperately in need of TLC for £3k
Total = £12k.
If you wanted 100 hrs, it would come out at about £6000 to go and fly a cheap rental around Oz and about £4k with something like a Minimax. Looks like the break-even is probably around 80 hrs.
Just making the point really that there are more than one way to skin the cat.
G