You must remember that 11.8 in 100m for Haile is not the same as a sprinter. He will loose much in the start. I read from an interwiew that he did 49 in 400m.
I belive that evry distance runner who can do around 23,5 in 400m also Canova pupil N. Kemboi
Kenedy Numbers I found from an American book were he was interwievd.
Also Marius Bakken has PB of 49 400m and 1.51 800m (but some time ago)
Ofen the best distance runners (white) start as sprinter and 800m runner. You need both Speed and Endurane.
Some say Lopes was a 56 400m runner. I think he did 56 last la of a ca 27.20 10k while Mamede finish in 54 last lap.
Develop Speed and endurance always, then conect them with speed endurance before track season. For 400- Marathon
Bjorn, 11.8 is with a running start.
As for Kennedy, what book did you read this in? What article was Gebrselassie's PB listed?