The main issue is availability of the socket. Also, it is tiny and may not hold up too well over time. The Senn headphones all use part of the frame to grip the connector body. It might not be easy to recreate that. Plus the connectors themselves aren't the easiest to work with (although they are certainly compact).
Mini XLR's are great. If those are too big, you could go 3.5 or 2.5 mm plugs/jacks, although you probably want locking ones.
Moon Audio uses a coaxial variety of a mini Lemo connector. Senn HD800 use a 2pin mini Lemo. Expensive solution. Mini XLRs, if they fit into your headphones are probably the most secure, economical way to add detachable cables. You could also use Hifiman style coax connectors. Those are dirt cheap too.