Update: It seems that there's not OLED back-display, only an OLED viewfinder, see translation below
Back in March there were rumors that Sony's upcoming Alpha A77 DSLR will have an OLED viewfinder. That camera is not official yet, but Sony did submit it to a design contest - and from that page (which was taken down in the meantime) we can see that indeed it has an XGA OLED electronic viewfinder (or Tru-Finder as Sony calls it). We're not sure, but it also mentions a second OLED display - perhaps the 'normal' camera back display will also be an OLED (if someone can translate the Japanese text below, it'll be great).
The viewfinder resolution (XGA, or 1024x768) is rather a disappointment - as it was rumored that this will use Sony's 720p (1,280x720) resolution. There were also some rumors that eMagin is behind that OLED microdisplay. While eMagin do not have an XGA product, they have mentioned that they are working with a customer on a special 'commercial' microdisplay, so this may be it (disclose: I'm holding some shares in eMagin...).