Xvim:
Wether or not Morality truly is set in stone or up to local custom is obviously up to the DM or the Published material.
Hving your own moral code NOT be good tho, which is what i meant when i said it isnt moral relativism, is quite interresting.
Coming to terms with that, or to express yourself as a fantasy villain.
You might actually go a bit biblical with this, especialy when it comes to freedom and authority in the face of gods. The NWN2 xpac comes to mind.
as for "some might be not evil": i think the important bit about this, and about makign a character like this, is that NOT beeing evil is a voluntary act.
Actually a struggle in itself. To defy ones own nature.