As it happens I know a bit about the China Air SP that lost #4 and did the aeros - the LAME who did CAL work in SFO is an old drinking buddy of mine. Yes, the airframe was junked. The fin was bent to the right about 5 degrees and the stab was missing about 20 feet on each side - lucky or what??? That night I was leaving SFO for points east and he took me into the (locked!!) hangar and I saw for myself the damage.
The story he got was that there was "a problem" with #4 and it failed at FL410, but the crew didn't notice. The a/c naturally slowed as the autothrottle applied max thrust and nothing was done until buffet. In the meantime the a/p had stuck in max aileron (no rudder authority in crz) and, as the a/c departed the crew disconnected the a/p, let the aileron centralise and the rest is history!!!!
During the recovery the G loading popped the u/c doors which promptly departed the a/c and hit the stab removing about 20ft symetrically. The gear stayed on the locks.
The investigation uncovered just plain terrible rostering practices which meant that the crew, esp Capt, had only had a tiny period of good rest for several days.
As always, more than 1 simple cause for a very serious incident. Mr Boeing sure builds 'em tough!!
WRT looping the classic B747, it was (is?) a standard fun thing in the sim. Barbers pole on the descent from 20K, gently (well, not too gently) pull through and as the a/c goes inverted over the top select F5. Put it away fast on the other side, though!!!
Of course this is almost certainly outside the flight model the sim computer has, so I've no idea at all if it works in real life.