Thanks for the info, mate.
The tub I have is a 200 liter from Bunnings that I got to place them outside for some sun. They actually weren't that expensive for the size, but are not as heavy duty as the ones above I don't think. I just felt that it was too small for a permanent home, but by building up the levels like you have done and adding the lid, you can almost triple the floorspace. They are a little longer and narrower than the ones above, but if I place it so it captures the sun it should be work fine. I'm thinking I might put it on castor wheels to make it easier to move around, but i'll have a play with it and see what works, but certainly inspired, thanks.
Those round tubs look great, but they are expensive from what I have seen. The IBC conversion is definitely something I want to try, I have found them going pretty cheap on gumtree and facebook, plus it gives them a little bit more space by the look of it.
Agree with using the big yellow thing in the sky, but being in Melbourne, i'm limited in what I can keep outdoors year-round. I'm trying to free up some indoor cages for other skink species, and with these tubs I could potentially put black rock, tree and whites skinks outside, and get some land mullets, major skinks, etc. for inside.
Thanks again, much appreciated.
Rick.