Another rumour (!) was that there was also a feasability study done on fitting AAR kit to the Shacks. It was going quite well until it was pointed out there were no Avgas tankers!!
Another problem with tanking a Shackleton was to find a tanker that was slow enough to give the fuel, even if capable of AVGAS!! If I remember, range speed was about 160 kts? (Friday afternoon cruise was 180 kts with endurance at 140 kts). Flying into a headwind, we were regularly overtaken by trains on the East Coast line.
Surely we already had one, another Shack, if you were going to the trouble of fitting a AAR capability, you might as well throw a pod on it.