Going back to the 'rathered' conversation - is 'rather'd' an acceptable shortening of 'rather had'? It doesn't look good written down, but it sounds like something you'd hear in speech.
I'd rather'd you'd given me that cake.
Kind of, but it's best to avoid it. It doesn't stand up to any scrutiny, because the "'d" (had) after "rather" is redundant, as it already sits after "you".
I can't think of a time when you'd say "rather had", actually.
Going back to the 'rathered' conversation - is 'rather'd' an acceptable shortening of 'rather had'? It doesn't look good written down, but it sounds like something you'd hear in speech.
I'd rather'd you'd given me that cake.