Can Aquaponics Pay for Itself?

Aquaponics usually stirs up a good deal of interest and debate here. From the awesome urban aquaponics of Growing Power to industrial-scale aquaponics operations, plenty of people believe in the idea of recycling fish poop into plant food in an efficient semi-closed-loop system. And yet questions remain—I've asked before whether aquaponics is cruel, whether soil-less farming can be organic, and whether aquaponics is an efficient way to feed ourselves. Now one study is claiming to answer another important question—can aquaponics pay for itself?
In theory, the idea of a semi-automated backyard food growing system that can produce both high-quality animal protein, and fresh, organic produce would seem like a no-brainer from an economic standpoint. But there is a significant cost outlay involved in setting up an aquaponics system—not to mention a learning curve on keeping it running.
Now Backyard Aquaponics—the Australian makers of aquaponics kits, and publishers of an online aquaponics magazine—are claiming that an independent cost-benefit analysis has proven that one of their kits can pay for itself in as little as 2 to 2.5 years. Furthermore, they are claiming these numbers are based on conservative estimates.
The Cost/benefit Analysis of Aquaponics Systems (PDF download) was created by a Richard Chiang who, it should be noted, appears to be an advocate for aquaponics in the Canberra region of Australia. It was also based on figures for energy usage, labor needs and estimated yields that were provided by the kit suppliers themselves—so this is by no means a definitive study of the economics of aquaponics.
Nevertheless, it's good to see folks putting some numbers together on the viability, or not, of this potentially promising field. I'd love to hear from other aquaponics practitioners about how aquaponics shakes out from economic perspective