While procedurally generated asteroids using PQS and the celestial body system would be quite cool, it would also be very difficult to implement, as KSP wouldhave to export the scaledspace model and textures each time new asteroids were found. There's probably a workaround, or instance, maybe you generate the asteroid model not with PQS, but as a huge conventional model (just like asteroids already) and you center them on an empty celestial body with no terrain. For ScaledSpace, the planet could just re-use a small-scale version of that model. Or you could just have the game generate low-definition scaledspace maps of an asteroid that does have PQS, and wait a while whenever the textures need to be generated. 64x32 textures for a 5km object would be reasonable.