Hi,
Just wanted to share with you my experience, I have ordered a mp3 player from ebay for 2.50$
and it has a tiny 128x64 display inside, so I hacked it and got the display to work.
Some info:
its and LCD/LCM?, it looks like OLED but it not it just have a 2 color background resulting it to look like the two color OLED
Single LED backlight
Display Driver is UC1701
3.3V operation
128x64 Pixels
SPI (5 pins) Communication
Dimensions (metric):
Full: Width – 23mm | Height – 20mm
Display: Width – 23mm | Height – 15mm
Actually Pixels – ~2.5mm crop on all sides
Got it running with u8glib, thank you Oliver 
All following constructors are working:
U8GLIB_MINI12864 u8g(10, 9, 8); // SPI Com: SCK = 13, MOSI = 11, CS = 10, A0 = 9, RESET = 8
//U8GLIB_MINI12864 u8g(13, 11, 10, 9, 8); // SPI Com: SCK = 13, MOSI = 11, CS = 10, A0 = 9, RESET = 8
//U8GLIB_MINI12864_2X u8g(10, 9, 8); // SPI Com: SCK = 13, MOSI = 11, CS = 10, A0 = 9, RESET = 8
//U8GLIB_MINI12864_2X u8g(13, 11, 10, 9, 8); // SPI Com: SCK = 13, MOSI = 11, CS = 10, A0 = 9, RESET = 8
Setting the contrast value to 190 in setup gave best viewing results
u8g.setContrast(190);
pinout and picture attached
full info in my blog : http://overskill.alexshu.com/cheaphack-a-2-5-chinese-mp3-player-for-its-128x64-mini-lcd/
Not the best quality, but, IMHO this screen at this price is a bargain.
