I understand not wanting to disturb whatever balance is going on in the hive, but what would it hurt to open the hive (with the owners permission), remove a frame of fresh eggs and start a nuc to allow them to raise a queen from their own offspring?
I don't think this would be too invasive and could produce what we have all been looking for. I'll take one of the resulting hives.
Of course, catching a swarm would work the same way, just not as quick and with the current old queen (singular, not plural the way you could harvest queen cells if the new nuc would raise more than one).
If the hive has been untouched for years, I image the burr comb and propolis will make it pretty difficult to remove a frame of eggs. Not without causing a major disturbance.
Even if you did get some eggs and raise some queens, you would have to do it in the same vicitiny so as to get the same drone lineage during mating that the hive queens would get.