If the vanilla SAM3XE chip like you can order it from Farnell works with own-built boards, I might develop a smaller version of the
board.

I have a few of these boards laying around, and I have a few more of the SAM3XE chips. I'll see if I can get a few of the SAM3XE chips and see if I can get them to work. I'll also see if I can get the SAM