Axel Dorfler (developer of Haiku) said that Haiku will run on PowerPC machines (Pegasos).
He was given one especially for the purpose of porting it.
Look at the 4th and 5th pictures down
here :-)
If Haiku can run on PowerPC machines, is it possible to port it to AmigaOne, uA1, Amy05 or PowerVixxen LT
Shouldn't be much of a problem.