Rivendell Rohloff (now, for something completely different)
It's quite an honor when someone is so happy with they work you did on their recumbent trike, that they want you to do a really special thing on a different cycle they own.
Recently, a gentleman with a Rivendell touring bike came to me for a Rohloff customization request. The challenge is to put some kind of do-hickey on the bike that will accept a conventional Rohloff torque arm system without actually requiring the hassle of using a torque arm (they make tire fixing more of a challenge than it needs to be.)