Turtle stock-tank help needed

[Kitah]

Hey guys, I've finally decided that I'm definitely moving off campus next year so I can have my cat and turtle up at university with me. Turt is an adult Kreffts, about 25cm carapace length. For a number of reasons I'm certain that I'd be better off buying a new tank/enclosure for him in Townsville instead of bringing his current tank up; simply because of the risk of breakage as its a long distance drive, and also because during the holidays I'll want to have him at home with me, which would mean that I'd have to drive the tank back down (Though there's no way it would fit in my car) so It'd be easier to have one tank in brisbane and one in Townsville.

A while ago I drew up a "plan" of what I'd eventually like to house turt in, and I started wondering if I'd be able to set him up in this in Townsville, seeing as he'll have to get a new enclosure here anyway.

Heres a pic of the "plan"

Its basically a stock tank with a timber frame around the actual tank to "pretty it up" and provide storage, and it would have a steel frame on top which I could lock with a paddlock and would keep predators out.

A few questions though;
1. Does anyone know where I could get a stock tank like this? I'd prefer it to be at least 300 gallons, preferably

2. Does anyone have any other ideas? (keeping in mind I'll be renting so can't make an inground pond or anything)