Actually they often do produce hail. However this is usually limited to the freezing level (about 10,000 feet) in the stronger convection and melts before it reaches the ground. Hurricane convection generally lacks the vertical instability to produce the really strong up/downdrafts conducive to large hail-most of the energy is horizontally stratified in the system's high winds. The recons have reported hail at flight level in several hurricanes this season. It seems to become more common as the systems move north and interact with continental air masses in their outer feeder bands.
Speaking of convection, I noted that the leading feeder band on the west side of Frances, as it moved offshore south of Tampa, suddenly started producing HUGE amounts of lightning over the Gulf, as opposed to few strikes over land. Interesting.