Imagine the double-slit experiment where the particles emitted were black holes the mass-energy equivalent of sub-atomoic particles. Would they form an interference pattern?
So one of the issues is "what is a sub-atomic black hole?". At the extreme it is a black hole with a planck-length event-horizon diameter. The slits would occur if three additional black holes were arranged linearly such that there is a small distance between the event horizon of the central black hole and the two adjacent black holes - one on the left, one on the right. The space between would be perhaps 2 planck-lengths.
The detecting structure measures the planck-length event-horizon black holes as gravitional disturbances. The resulting pattern will or will not show an interference pattern. I claim this experiment would show an interference pattern since quantum mechanics demands it - otherwise quantum mechanics does not apply to all sub-atomic phenomena.