That really sounds like an electrical problem to me. I'd take that mouse apart and examine all solder connections with a magnifier. I had something similar happen several years ago with random cursor movements and random clicking of 'things'. It turned out to be an intermittent short in my keyboard that started the whole mess.
i5 3570k, ASRock z77 Extreme 4, 8 Gb Ripjaws 1600, Antec 430w psu, HVR 1600 tv tuner, custom case- marble top, oak face. Carver & DCM Time Window sound system. Mint 14 KDE.