I argued in two previous posts (here and here)that the so-called "common error" of should of, could of etc is actually a change in the grammar of English and today I came upon some very good supporting evidence.
And yet companies are constantly being sued over patents which are so broad or trivial they should've never been granted in the first place. [ Slashdot ]There we have verb verb adverb(time) past-participle. The adverb is after two verbs... that can't be right. I mean, I will never do, I would never do, etc.
And if you have a look at Jane Austen's Emma on Project Gutenberg, you'll find that "have never" only occurs in the present perfect, and that when using other compound tenses, "never" goes between the first auxiliary and have.
If we can say I would've never known, then surely would've is now a single word in the internal model of a great many native speakers...?