Hi randoma,
Is there any chance you could post the entire .cpp and .h files with your modifications? The code modifications that you posted appear to be incomplete. Of course, it could just be me...
Here is a link to download entre code.
http://todotani.cocolog-nifty.com/blog/files/ks0108.zip
For your information, this code is optimized for Arduino Maga, and dose not work with other Arduino board like Duemilanove.
Here is other optimization.
http://todotani.cocolog-nifty.com/blog/files/ks0108_wb.zip
In this version, instead to write data to GLCD in each column address, block transfer entire 8 lines when call GLCD.Update() function.
When I call Update() function 5ms interval (equivalent to 24Hz refresh rate), this version can mark 20 FPS.
Here is link to my blog to explain above modifications. Sorry it written in Japanese only, but you may find what I'm writing with machine translation.