FlyEFJ: Sorry, but you ARE wrong about the speed/flap relationships on B747-400 ( and B777) In Vnav or G/S capture mode the aircraft will fly the selected speed regardless of the flap setting. Therefore you could get the aircraft to fly clean at a speeds well below a safe value. Its a long time since I flew the 747-400, but certainly on the B777 you will only get protection from a low speed condition when the autothrottles activate as the speed approaches the stick shaker speed. This would only happen if the autothrottle was, at least, in the armed mode and would keep the aircraft flying for the hopeful PPL.
With reference to earlier comments about the article in Pilot magazine, I have to support Bob Grimstead's ( the co-author) observations 100%. It is absolutely true that -5 kts into the flare on a B747 ( or any big jet) can lead to a severely heavy landing or a tailstrike, conversely +10kts means a huge amount of extra energy to dissipate. The B747 has a massive wing and floats beautifully in ground effect. You cannot begin to get rid of all that energy until the aircraft is on the ground and spoilers and brakes can do their job.It WILL float for half the runway if you let it.
I was a training captain for many years in Big Airways in the days when it was possible to let friends and the public have a go at flying a B747 or B777 simulator. Private pilot or microsoft expert or not, even with a talk down, none succeeded in getting the aircraft anywhere near a survivable landing on a runway despite several attempts. A PPL might get the B747 into the semblance of a flare, but the landing would either be dangerously fast or slow, the flare too high or too late and almost certainly into the scenery rather than on the runway. The chances are about 1 in a 100 of getting it right. You would be sensationally lucky if you did. At best you could prevent an uncontrolled descent from altitude and you might enable a few people to survive the controlled crash.