A couple of comments about refurbished FWs and prices...
First, you don't know what shape the machine was in to begin with. If it was severely damaged by crazing of the paint and/or oxidation and the paint eroded from the machine to the point where it was unuseable something had to be done. Two choices - toss her in the dump or refurbish her. If you toss her she has no life left, no more sewing to do, no more joy to give. If you refurbish her she has many more years to go. If you refurbish her the question is what color. I submit if you redo her in black you are not doing anyone a favor who may buy her thinking she is original and in pristine condition. Not fair to a buyer who would pay $700 for a pristine FW (they are out there, believe me, just follow ebay bidders long enough and you will see). So, I think your only choice would be to paint her a color that was NOT original. Now, orange may not be your choice (but I happen to love it) and, BTW, $700 is not outrageous given the cost of the machine to begin with, stripping it down, painting it properly, and reconstructing the machine in proper, well-working condition. Plus, if the machine was in really bad shape it probably didn't have a case and may have needed parts to put it into running condition.
Just to recap, although I would never, ever, repaint a useable FW, I see no harm in redoing one that is not useable. But to be honest to future buyers by not putting out a machine that could be mistaken as a pristine original I would never have one repainted black. You cannot misrepresent a FW painted any color other than black, tan, and white to a knowledgeable buyer. I might even conceed that it would be real hard to paint a machine to reasonably masquerade as a white or tan machine to a knowledgeable buyer.