if the 1011 has no takeoff redundancy in an engine-out ferry, then a twin is no worse.
Actually, from the viewpoint of another engine failure, a twin is surely 100% better off. It has only half as many engines remaining, so a corresponding chance of a failure.
Very simplistic, I know, and probably a light-blue-touchpaper job.
Looking in from the outside, I am guessing that the problem with a single-engine ferry is that you are starting with only 50% of normal power available, whereas with a three- or four-engined aircraft you have respectively 67% and 75%. And I also guess 50% of normal maximum power is simply not enough to take off in your average commercial twin.
Once again, I realise this is a very simplistic view.