I am also looking into scale use for brushless motors. You can certainly run brushless motors below their recommended voltage, I have been trying out brushless in a Perkasa. Not just suitable fast scale options, but also low end, low voltage uses. I have comfortably run a 3s/4s specified motor down at 6v, or just shy of half its recommended voltage input, with no noticeable issues. This was with a smallish diameter 36mm prop.
There may be issues as the load increases with bigger props ( A fellow Mayhemmer on here has tried brushless, down and dirty, in a rock crawler, but found the low end torque was very poor, at low voltages, through the reduction drive compared to traditional brushed motors. ), but I found the current drain down below motor specifications, was very low.
I am looking for that pot of gold option, lower current drain than either geared or blower type motors. I am currently looking at the 'pancake' style brushless used by bigger quadcopters as a possible option. Big diameter can should equal flywheel like torque effects. But my first job will be to over prop and under volt the Perkasa ,hook up a watt meter and see what we shall see.