Mitsubishi is showing their new Diamond Vision OLED modular screen at CEATEC. It seems that a 150" screen costs $400,000. Mitsubishi says that they can provide the display at "unlimited" size, and it can be delivered in a curved design. Check out this great video:
The Diamond Vision OLED is already shipping, and Mitsubishi has installed the first screen over at Merck's new Material Research Center in Darmstadt, Germany.
This is the big OLED screen at Merck's Center - just found this picture:
http://de.wikipedia.org/w/index.php?title=Datei:OLED_02.jpg&filetimestamp=20100924152905