So I did some research and found out that the Prolux vacuum cleaner trademark has been owned since 2011 by Rocky Mountain Vacuum Brokers LLC of West Jordan, UT, which was founded in 1998.
I wonder if the company is owned by former Electrolux management or if it's a division of Aerus Holdings LLC? Regardless, sometime around 1998 Electrolux LLC dropped the Prolux vacuum cleaner label on its commercial uprights and its retail line CB2000 power nozzles. It had used the trademark since 1987.
Interestingly, the Prolux name does not seem to be restricted in its ownership as other companies also use it--including a New Zealand fittings company, a towing parts company, and a manufacturing company.
As for current Prolux vacuum cleaner manufacturing, I found a Prolux 7000 upright on the Simplicity website; so that would indicate a Tacony product labeled for Rocky Mountain, TTI and others. I didn't do a thorough search for other Prolux vacuums on Simplicity's website but am guessing that they, too, are manufactured by Tacony.