Hmmm... Now you have me thinking crazy.... How about if one were to select a root stock and a cutting of approx the same diameter and preferably a bit over 1/4". Then using a drill bit selected to be about 1/8" smaller than the root stock, center the drill bit over the root stock and carefully core out the center down to about 3/4 - 1" in depth taking extreme care to only core the center while leaving the external cambium skin intact; essentially creating a cambium cylinder on the end of the root stock. That done, take the cutting / scion and after making a fresh cut on the bottom, slightly round the bottom to a convex tip and then mark the cutting at a point about equal to the depth of the cylindrical cambium tube just made on the root stock and hopefully about 1.5 - 2" below an obvious mode. At this point, if one were to slightly shave the cambium layer on the scion from the tip to the mark just made such that the scion tip is thinned and tapered a bit without completely shaving the cambium off of any part, one could then marry the cutting to the root stock by inserting the shaved point into the cambium cylinder downward until the cutting was seated against the root stock core and fthe tip was fully enclosed within the cambium cyclinder. Essentially creating a fishing rod type of joint. The grafted joint could then be sealed as per normal procedures to ensure a tight seal... I wonder if this would work.