Hi avenue33, Graynomad,
If you (or anyone) are interested in my lib., let me know and i will mail it. You are right that most libs are for the smaller sized displays. Maybe we could use at least the same syntax for the basic commands.
I have rewritten 'my' lib. a few times for learning and i decided on a 'base' class/lib with only the commands from the command sheet, tried to follow their syntax/wording/behavior as close as possible. I planned on extending functionality in separate classes and/or headers. Thus far i have, apart from most of the basic commands, made a (proof of concept) class for bargraphs and another one for histograms. One of the things i would like to add is a filesystem class for using the sd-card with the FAT filesystem instead of 'raw' access.
As i started with an Arduino Mega1280 i made the base class accept any of the hardware serial ports as a constructor argument. Another thing i would like to implement is incorporating the softSerial library to free the single hardware serial port on the Arduino UNO or duemilanove type Arduinos. I chose to incorporate the serial communications inside the library to be able to optimize the communications in the future. (dreaming about custom buffer sizes, non blocking commands and so on. 
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It seems the 4d-systems modules are becoming popular. I like them apart from the price. Also i think the shield they have is a bit limited. No circuit for buttons or sound, only hardware serial port usage.
Regards,
Jeroen.
Yotson on irc://freenode/arduino