Just got an idea.
You could stick a small belleville washer (or two, they can be stacked nested to double spring constant, or facing each other to double displacement distance) on the back of a spherical washer (to provide the angle), and the belleville stack could offer some additional linear movement on each spoke, perhaps 2mm per spoke from the belleville washer stack in addition to whatever linear movement you can gain from the spoke stretch (which isn't much with the very short spokes). This could perhaps make a short-spoked hubmotor wheel capable of distributing an impact load over a very wide group of spokes, just like a normal long-spoked bicycle wheel.
This could be the long-term spoke reliability solution for big diameter hubmotors laced up with short spokes.