Hi hacker007,
yes I'm currently working on it.
What I have so far is:
1) a bootloader for mega32 and mega644p
2) a new hardware core that defines a better pin numbering for the net-io
3) patched versions of EtherCard and etherShield for networking
I have some examples tested successfully.
But of course more testing has to be done!
For the AddOn board I've the following libs:
LCDI2C4Bit LiquidCrystal_I2C RF12 SdFat
Some examples running.
The RF12 seems to work with RFM12B but not with RFM12!
So I would say the core and bootloader are beta.

The libs are alpha state.
If interested I can provide some sources in the next days.
Update:I've started a project for porting arduino core files and libs to the AVR-Net-IO.
I added a new core (avrnetio) to support the ATmega644(p) and ATmega32 and a bootloader.
As far as possible I made the changes cpu independent and put all board specific stuff in one file (board.def).
Libs are patched with #ifdef to work with arduino boards as well as with AVR-Net-IO.
url:avr-netino.googlecode.com