rubik,
My Boeing 737 Operations Manual in the section for Engines, APU (page 7.20.8 paragraph 3) states quite clearly: 'The thrust reverser can be deployed when either radio altimeter senses less than 10 feet altitude, or when the air/ground safety sensor is in the ground mode. Movement of the reverse thrust levers is mechanically restricted until the forward thrust levers are in the idle position'. There's no and in there (or even AND).
Undesirable it may be, but possible.