can't you just sort all as int? the codepages usually come roughly sorted, and while no one knows which of 檎 or 橙 comes first, I don't think it'll be particularly offensive whichever way a random app did, to most.
That would be one locale-invariant sort as I said. Sure, you can pick some way of doing it that's least-bad. The codepages are roughly sorted, but what we're debating is the cases where that fails some definition of correctness. The point is there can be no universally correct answer for sorting locales before the user picks one, because that can depend on already knowing the locale itself.
There is no such thing as standard codepage numbers.