I used avarice in the past with great satisfaction for debug applications on atmega devices. Actually I'm switching for new projects on atxmega devices and I didn't found any support for them. I browsed svn history and found some iìntegrations like 6 weeks ago. I actually have some demo chip of ATxmega64D3 I can test them with new avarice versions and try to get them working if someone helps me on how to start.
Please, give me an help getting rid of AVR STUDIO, I don't want to use it anymore :) I love avarice.