Back in September 2015, Canon announced that it was developing a 120 megapixel CMOS sensor. Now, you can buy the APS-H-sized sensor (in RGB or Monochrome variants) from authorized distributor Phase 1 Technology Corp.
Phase 1 doesn't actually list the sensor's price on their product page, but from what we've been told, it'll set you back a cool $12,000.00.