There have been reports of an aircraft flying, during the daylight, around Area 51, that looks similar to an F-117, but is a two seat aircraft, about one and a half to two times the size of the F-117. It's reportedly a later generation stealth aircraft as it isn't faceted.
It's also been reported that there are approximately seven manned platforms that have been flown/flight tested, at a minimum, that are classified, based on reports of the histories of various test pilots. One of these test pilots reportedly holds an "altitude record" for having been the one to fly the highest and open the weapons bay of one such aircraft.
Until any of these aircraft are de-classified, or at least have a reduced classification, I doubt we'll know much about them.