I know of a guy who will do custom's and will do double edged, but I have yet to see one of his finished balisongs. All the pieces that I have seen over the net are fine looking and I have only heard good things about him, but I cannot be 100% sure of the quality. I am planning on getting a piece made by him in the near future and if you want to wait, I'll put up a review. I was actually going to get it started this week, but I had 2 bali's come my way that I really didn't expect, so I picked them up instead which put a bit of a delay on the custom.
Email me if interested and I'll hook you up with the info.
Tique