Really dont see the point on running on MorphOS on such slow hardware. For cheaper than it will take you to put that machine together get a mac mini.
I have to agree with JJ on his point that spending the money on an Efika, for which I own and have a registered copy of MorphOS installed, would be throwing money at an inferior system. I have a Mac Mini G4 1.5 with an unregistered copy of MorphOS and it simply flies when using it. I got the Efika when it was the cheapest option to run MorphOS, but certainly now there are other options with better performance and require less money to get that MorphOS experience.
The Dawg