Mitsubishi has found a way to create OLED screens of unlimited size. In fact, they arbitrarily stopped at a 155 inch diagonal demonstration screen for the CEATEC 2009 show this week in Japan.
(Mitsubishi OLED tile video from CEATEC 2009)
The secret is - screen tiles. Mitsubishi has created OLED screen tiles that look to be about four inches square. Combine them in arbitrarily large numbers to create a screen as large as you might want.
The obvious drawbacks are the fact that the native resolution of the pixels is relatively low (about 4 millimeters) and the OLED lights will only last about 2.5 years in typical use.
Still, this technology, which will probably take another 3 years to reach the shelves of your local tech store, would be useful for putting displays in unusual places.
Science fiction writers have given us a variety of similar ideas to chew on. Take a look at the entries for Illuminium tiles from Altered Carbon (2003), randominoes from Nymphomation (2000), data tiles from the Minority Report movie (2002) and maybe even video wallpaper from A Deepness in the Sky (1999).