How about extra bobbins for her Bernina and new 1/4" foot if she doesn't have it. Lots of great suggestions. I have the Go machine and like it but it's a personal thing. Maybe a small gift basket made up of some of the items listed here and a gift certificate wrapped pretty with some of her favorite coffee or tea items and cookies etc.
And yes, let her read these posts. My DH is thoughtful but he would not go on line to get help from quilters......probably wouldn't cross his mind.
Have fun gift hunting!