Update: OLPC display's aren't exactly Pixel Qi displays, read more below
Pixel Qi's CEO Mary Lou Jespen reports in her blog that over 3 million Pixel Qi displays have shipped to date - and they are ramping up for higher volumes. She says that these displayed are used in OLPC laptops, several tablets and netbooks and security/military devices.
OLPC displays aren't exactly Pixel Qi displays. We have talked briefly with Mary, and she explained to us that Pixel Qi was spun-off from OLPC - to commercialize the unique display technology. The two companies have a royalty-free cross-license agreement, and the Pixel Qi displays are more advanced then the first-gen product used in the OLPC laptop.