Other World Computing demonstrates the new Retina Display MacBook Pro powering three external monitors in a new post on their blog, notes MacRumors.
By connecting two Thunderbolt displays and third monitor using HDMI the setup powers four screens for a total of 15,680,000 pixels.
"Moving images and media didn't create any lag and we were able to play video on all four displays simultaneously."
Apple actually supports this setup noting in a support document that "MacBook Pro (Retina, Mid 2012) can support an HDMI-compatible device on its HDMI port while also using two Thunderbolt displays."
Read More [via MacRumors]