Well, that went considerably more smoothly than I expected! I finally got around to ordering and using a Wisdom Panel DNA test kit on my wife's dog Lily, who is eight years old this month. It involves using a couple of swabs between the dog's cheek and gums, and seeing as how Lily gives a whole new meaning to the word "contrary" I was expecting resistance...but we caught her early in the morning as she was half asleep on the couch and she was fine with it, relatively speaking.
We should be getting results back in a couple of weeks. This should be interesting.