I'm not sure about the reasoning behind those external fans, nor if the fans would die fast if they were spinning in the oil. As far as I could tell all the fans spinning were due to them being powered, not because of bubbles or convection currents. Taking into account that even water cooling needs a pump to keep cool water flowing to the hotspots, I'm not sure how well a bare chip would be cooled based on convection alone.
The pumps used to generate bubbles isn't neccessary and can be removed. I've also seen other builds where the powersupply is dunked in oil without immediate adverse effects. An SSD would go in the oil just fine, but since they don't make noise there's no real point. Optical drives can always be replaced with external USB options that are plugged in when necessary, so it really only leaves the power supply as the one necessary source of noise.
If you decide to get a quiet one (like mine, and it stops spinning at low output anyway) then it's pretty good.