With java USE flag enabled, openoffice-ximian wants to emerge blackdown-jre even though I have kaffe-1.1.5 installed. The reason for that is that xoo requires >=virtual/jre-1.4.1, and kaffe's version is 1.1.5 -- this is considered a bug in Portage, as much as I understand. Until it is fixed, I suggest that xoo would depend on virtual/jre. I know kaffe isn't a complete implementation, but since the default package to satisfy virtual/jre is blackdown, only users who explicitly emerge kaffe would use it, and those seem to know what they're doing. ;-)
Did you actually ever try to build it with kaffe? Did it work? And does it run correctly? Cause if not, there is no point in doing this. Other than that, your sugestion is not practicable, as this would break the dependencies as OOo does not build / work correctly with most jdks < 1.4
No feedback, also the proposed change would break other jres so closing