I also needed to get a portable QT pond, and searched the internet. I eventually settled on buying one from Minurphy Tarpaulins in DBN. They have a 2m and 3m diameter (between 2400l and 5300l). It has a custom made net which is essential for QT purposes. The cost was +- R2500 for the smaller one and R3000 for the larger pond. They look like the vats used at koi shows. The day after confirming order and doing the EFT the pond was delivered to my doorstep. Courier costs from DBN to Pretoria was R276.
Very easy to set up, and ceratinly appears more durable than the Intex pools. Also very compact for storage when not needed.
If interested just google "minurphy" and contact details appear in the links. They don't have a website.
The way you're buying and selling koi, I think you need a longer term investment!