And that interview doesn't really say anything at all ("If you were a Leica developer, and if you were to find a way - and, nudge nudge, everybody note that I am using the subjunctive mood - to put a full-frame sensor in there, you would probably do it, wouldn't you?")
Since everybody already knows that if Leica can get it to work for an acceptable amount of money, they will do it, Kaufmann is not really saying anything at all except playing with the wishful thinking of his readership. This is not a "source" for anything substantial either. The whole discussion is a lot of hot air.
Philipp