Holders of single pilot waivers, submit their flight hours to the manufacturer, who then submit that info to the FAA...as does the training facility sends completion or failure of single pilot training to the FAA.
According to the person who managed the single pilot waiver info as Cessna in Wichita, only about 500 or so pilots have ever had the SP waiver, and that goes back to the 80s..
So when you say 'many of us have had waivers of a variety of FAA types'....not only is 'many' a false statement but the CE500 series are the only jet where you can get the SP waiver.
Now since the FAA issues these waivers and is ICAO, just like most of the world.....while they don't issue waivers in Mexico or Canada, they can't tell me I can't fly single pilot...not if they want to be ICAO.
Now I have heard France, grounding Falcons that don't have typed SICs, but that's France.....something tells me, if I flew around Europe single pilot in a Citation...the UK, Germany, ect would respect my waiver....especially if they want our FAA guys to come over and inspect their airports, approach equipment, airspace, investigate accidents, and accept your pilots coming over here without proper sim training and types(Australians)...proper maintenance signed off by certified mechanics(everyone) and insurance from god knows who from your country....