Fortunately, there is an inexpensive solution if needed in the form of a 5.25" Graphics card PSU (450W), here. For only $20USD, it's not a bad solution, and is cleaner than running a normal computer PSU outside of the system, and having to jump the green and black wires together in order to get it to turn on (but this is still workable, if the user is willing).
The only problem I see with these kits is the thickness of the PCIe cables.
They seem to be really thick and the hole between PCIe section and ODD bay isn't really big. I recon that one cable will fit, but I wouldn't be so sure about two of them.