Of course, these power supplies are only suitable for cryptocurrency miners. Outside of that market, there's little to no need for power supplies that can deliver this sort of wattage. You can check out photos and specifications at AnandTech.
The Qdion QD3050 PSU is pretty funny, it's marketed as a "90Plus Gold" power supply. That label is used by a number of Chinese PSU makers, even though it officially doesn't exist.
Just like the 3.3 kW PSU from Afox, Qdion’s QD3050 90% ATX power supply comes with a massive number of PCIe power connectors to feed a dozen of GPUs with its +12V/248A output. The unit also has numerous SATA power plugs, but no EPS, so this one will not appeal to hardcore overclockers. One funny thing to note about this power supply is that it has a 90 Plus badge on it, which officially does not exist. In the meantime, a number of manufacturers from China are using it these days.
The Afox 3300W PSU reportedly has a price of $250 per unit when bought in sufficiently large quantities. That's pretty cheap, but we don't know anything about the build quality. Additionally, you're unlikely to encounter these units in retail stores, they're marketed directly to cryptocurrency mining farms.