Fraunhofer IPMS are showing an OLED based pico projector at SID. The projector is based on an OLED microdisplay by the Hypoled project.
The prototype projector is 25mm long, 18mm diameter, quite small (although not the smallest pico projector module). The OLED is currently monochrome only. The brightness is 10,000 candelas per square meter (a color OLED will be about half).