Any reason why the lib can not be included and shipped with the Repetier source? I have not looked at the license agreements, so I don't know if that is not allowed.
I have added support for the SSD1306 Oled driver, copied from u8glib, which is so much faster than the ST7920 based display. The SSD1306 requires only 1 byte per 8 pixels, unlike the ST7920 which requires 3 bytes for every 8 pixels.
It did require a few functions, like SPI functions and such.
I assume that very few users connect custom displays, so this will benefit very few anyway.