aaronpbrooks:
I know I'm a bit late on this, but did you ever get this display working through I2C rather than SPI? I'm attempting to do the same thing and have had a similar experience. Unfortunately (because of my own design) I need to stick with I2C. I've been trying to understand the reset, but with no luck thus far.
I can't speak for the Adafruit OLED however I am using a very similar display from dfRobot and I can confirm that the I2C address should be 0x3D when the DC line is pulled HIGH. I could never get the device to appear at 0x3C.
Should that be the case for you then I suggest the hack posted just above your post. There may be a way that does not involve changing a component of u8glib but I'm not confident enough to work it out.
For Oli, and reference, the device I am using is DFRTOY0007 OLED 2864:
... their site appears to be done but you can find some technical info here:
http://www.swbee.com/wiki/index.php/OLED_2864_Display_module_(SKU:TOY0007)