Thanks for the link and pic. I appreciated your pics in the other thread, Edgar, and agree that it's helpful to post such information as a reference--particularly if it's not already on the web. As for the tool set-up and other information on the Model 1572E/Discovery Plus, you may be able to get a copy of the owner's manual by contacting Aerus's corporate office if it isn't on the website.
It seems to me that the electric port was introduced on Electrolux uprights with the Model 1717/Genesis LXe (presuming that the 'e' referenced electric hose & port.
As I thought about adding a pigtail port, I remembered that this occurred on many Model Fs after the power nozzle was introduced in 1959. So, I would think, too, that the same could be done for the uprights.
Myles, is the upright cord on your Epic 3500SR still detachable, or are they now hard-wired? I'm guessing it's the 75h anniversary model, U110P. I like the oyster and fog color combination.