I should have asked this before, but can you still chuck the piece? Something to consider would be to turn out the collar (not really enough contrast for my tastes) and open the form a little so that an inset piece could be installed that would solve the problem of the flat area - perhaps Blackwood or something that would contrast with the ebony. Then work up from there into a transition area.
I still think there are all kinds of possibilities, but in order to rectify your concerns it seems the piece needs to be chucked.