Yes, this is really interesting stuff. I frequently use BD playlists to append extra material onto the front (and sometimes end) of existing streams, since it seems daft to re-encode an entire movie for the sake of a short logo replacement or added trailer reel.

I've used the playlist merge function in MultiAVCHD until now, but it's not a smooth enough switch to use for anything but a black and silent transition. BDedit might well give the solution, as long as I can match the asset properties.

RU.08, where does the 11.650 number come from? Is it simply a standard 'leader' length for branching clips?