Whoop, whoop! Loved your story, because I've been there. that's why I don't cut the whole quilt out at once any more! i hear my husband's voice in my head,'Measure twice; cut once.' I still take as much of my machine apart as I can, and it's usually a teensy, weensy bit of thread hiding in the most improbable place - or the top thread caught under the spool or in the notch.
Your quilt is beautiful. Has the look of a beloved antique.