It would be good to have a function like exo_binding_new_with_negation, so it is still unecessary to write a signal callback for two properties that are logical on the opposite value.
Why not just design your property names better so there's no negation?
That's what I did. I once had to change a "show" option to "hide", and I figured I had better rename the xfconf property aswell. So, no-go?
Can you think of a use case where renaming the property would be a problem? Obviously you can't rename the gobject property (unless it's one you've created yourself), but are there times when renaming the xfconf property name would be a really bad idea?
Really I don't find a use case. The most probable use case would be for checkbox', where it is not a big deal to rename the property.