I dont know if she would sign off or not given the circumstances. I guess the answer is no, there's no way in normal circumstances she would sign off on custody, but since I can drag this out 18 months if I choose, and depending on how badly she wants to be divorced and divorced now she might be more interested in signing off on full custody for me with visitation for her, or joint custody.
Really my only reason for doing this/concern in all of this is her moving off with my son. My wife is a runner, and her parents live a couple hundred miles away....she always runs there when there's a problem and even though she keeps telling me to trust her and that she's never going to take him away from me, she also told me more times than I can count that she would never leave me again either. Obviously she's broken that promise, so there's no way im willing to "trust" her on any other, she's gonna have to put it in writing. The only way I would even consider not fighting her for custody would be if she would agree to joint and allow it to be written in that if either of us moved from the town we currently live in, the other would assume full custody.
Again I dont think she'll go for any of that, but I also don't think im being unreasonable in asking, and because of that we're gonna end up in court fighting this out b/c I refuse to take anything less.....of course all of that is assuming she doesn't change her mind again between now and then and decide to work with me to fix things.