I seem to recall that RFDS WA tried an Avanti for patient transfer operations. For the aforementioned reasons the aircraft is not suited to emergency recovery work but has the speed for distance work. This was a couple of years ago now, I think. Dunno what the outcome was.
As for the Starship the problem was that it was a composite construction and the FAA had heart failure over the issue of fatigue life. Nobody could put a figure on it so the FAA decided that the airframe had to be overbuilt to bu@@ery and as a consequence the weight killed all the proposed performance specifications. However, some of the lessons learnt from the exercise went into the Premier 1A and Hawker 4000 jets.