I'm working on a patch before beta 1. The only issue is whether to raise in the case that order=True and the user specifies one of the 4 ordering dunders. I think raising is okay, especially since order=False is the default: you'd have to go out of your way to cause the exception. I'll mention functools.total_ordering in the exception message.

I do think that the discussion in my long message about __hash__ is correct, although I'm not done thinking it through. I think it's already pretty well tested, but if not I'll make sure there are enough test cases for objects that I think should or shouldn't be hashable that I'll have all of the kinks worked about before beta 1.