I don't know if one exists or not, but you could be the first to implement one!
There looks to be at least 5 digital pins and 1 analog pin left over; there looks like enough pins are left over to implement an SPI interface. Once you had that working (you would need another Arduino to play with this), you could then build a carrier board for the display on which you had the ATMega168/328 (for the SPI interface).
Personally, I would use the 328, since there is 2K of RAM on-board, and you could use this (with appropriate library functions - they don't exist yet) as a hidden buffer to draw to, then call a singular function to quickly update the entire screen in one fell swoop.
Additionally (and I don't think you would have to worry about altering all the code others have talked about when doing this, because I don't think controlling an LCD will depend on it - but I could be wrong), you could boost the frequency of the Arduino-based SPI controller to 20 MHz from the standard 16 MHz, for that little bit of extra speed on updates of the LCD and such (since at this point, you would be essentially building a graphics controller with the Arduino - every little bit of speed counts).
Then, to top it all off - besides the commands above (ie, write to buffer, blast buffer to screen), add commands to get/put segments of the screen (ie, sprite handling) and also add the ability to quickly draw triangles (for future 3D graphics capabilities!)...