I'm playing around with writing a patch to allow emerge to automatically
resolve use deps.
The basics appear to be working:
Calculating dependencies... done!
[ebuild R ] x11-libs/qt-webkit-4.6.3-r1 USE="dbus exceptions pch* (-
aqua) -debug -kde*" 0 kB 
[ebuild N ] app-misc/mytest-1.0.0 USE="kde" 0 kB 
however, not quite:
The following USE changes are necessary to proceed:
#required by =app-misc/mytest-1.0.0, required by mytest (argument)
Any pointers in the right direction would be much appreciated.