There's at least 2-3 boards that are being worked on for use with the Due, as default RAMPS will NOT work (3.3v drive to the FET's mainly, but standard RAMPS is designed to be 5V only). Adrian Bowyer has also contributed firmware for the Due, and others are also looking at/working on porting other types of firmware as well.
The problem with porting AVR optimised firmwares to a (somewhat) fast ARM processor is more than just recompiling the code. A number of shortcuts tend to be taken with the AVR firmwares that are hard to eliminate without a complete rewrite. There are also lots of optimisations on the AVR that will either need to be abstracted back out, or recoded completely from scratch. Also, there is no EEPROM on the Due you can write settings to, so you definitely need an SD card if you want that functionality.
People are working on it, but it's not easy.