Thanks for that.
He posts here, you could PM him.
The thing is, it’s hard to imagine who’d put the effort in.
Those most keen to minimise weight will already be using RC motors.
The small group of people using hubs as mid-drives (to achieve large gear reductions more easily than is possible for RC motors), use mini motors, which don’t have much fat on them.
A 3.5kg motor like the XiongDa, sure, but weight weenies won’t touch this motor weight class even if they could shed half a kilo from them.
You were interested in a 2.5kg Bafang, which is sort of a large mini motor. Knocking half a kilo off that might start to interest people, but not enough for them to be bothered when they can buy a 2.1kg AKM-100H instead.
The candidate motor would need to have some hugely redeeming qualities to make it worthwhile. If you can find such a motor, you’ll get help with it.