Jeff, Awesome pattern and cutting. That is one beautiful piece of wood. I really don't think it needs a frame. It would be hard to come up with one that would do it justice.
I just love this site. I learn something almost every day. It is great to have discussions like this. Don, I had never messed with the brightness threshold........I wish I knew that long time ago.
I would also use trace bitmap command and node selector to get rid of unwanted stuff. Not to try to complicate things..........i would put the image in gimp and erase the stuff i want there and copy and paste it into inkscape.