I think it is true to say that it is possible to 'roll' any aircraft.
Because if done properly, there should be no more than a very slight extra
strain on the airframe. 'Looping' a 747 is another matter entirely! You have
to pull a lot of G in a loop... I would, perhaps, be prepared to risk it in
a Flight Simulator though, providing I had a stiff whisky and a sandwich by
my side, and a couple of attractive (non PC) nurses to fan my brow
afterwards :-)