I read that the Germans coned their touch-holes in two ways: by going in through the breech with an egg-beater drill that had a right-angle drive on the end (small, fragile gears - sounds like a maintenance headache) or by using a small chisel through the touch-hole. This small chisel would just be a graver, and today we have powered engraving tools which would make relatively short work of enlarging the inside of the touch-hole.
One could put a touch-hole liner in a Queen Anne by going in at an angle. Making a right-angle cutter to fit in the small diameter chamber would be a bit over the top, but a graver could be used to open out at least the bottom and the back of the inside of the touch-hole. All one has to do is get some of the main charge close to the pan. Of course cleaning up the inside, whatever method is used, would also be a bit of work, but it's all doable.