I've seen a clever way to derive QM out of GR equations by making a single assumption: ds2exp(Cexp(-iwt)) = c2*dt2 - dx2 - dy2 - dz2. This extra exp() factor modulates the ds2 slightly, and when mixed with GR equations, it makes the time-dependent Schrodinger equation. Whether this math corresponds to any physics is a question, but if this idea is right, then the psi-function isn't some abstract "probabilities cloud", but rather a standing wave on top of the spacetime field governed by the GR equations.