Nikon recently (and quietly) replaced their LF-1 lens cap with the LF-4 (so much for Nikon tetraphobia), including the new cap with new Nikon lens announced since August. The new cap looks similar to Canon’s rear lens cap, the Dust Cap E (Rear).
Yay for super important camera news!
Update: Ranger9 points out in the comments below that the fact that Nikon is including “F Mount” on the lens cap seems to indicate that they will soon be introducing a major new mount. Perhaps it’s for a new EVIL-style line of cameras?