Do you also want 128 detents per revolution? Or could you use one with no detents at all? I don't know what a midi controller requires, but if you can do without detents, then a regular 24-pulse encoder like the PEC12R would give you 96 transitions. A "pulse" in the data sheets usually means a complete cycle of both switches, so there are four transitions per pulse. Then you could consider each transition to be an increment or decrement. I don't know of a 32-pulse regular encoder.