If you really want to go the whole quad, there were a number of reel to reel machines that could do it, the most recent was a Tascam machine, but a Sony TC 765 would do it too, big monster of a machine, break your back lifting it - but its dead easy to connect up.
You can still pick up quad reel to reel tapes and their performance is usually somewhat better than vinyl in terms of channel seperation - hardly surprising since there is no need to encode the channels. It can be quite impressive.
Shame B&O never had this facility on their reel to reels.