Both aircraft were taxiing simultaneously, in opposite directions on the single parallel taxiway. N5500C was east bound for takeoff. N69113 was westbound on the taxiway after landing on runway 27 and a turn onto the taxiway. The pilot of N5500C stated that they taxied from the parking ramp and prior to entering the taxiway did not see any aircraft on the taxiway. Nor did he recall seeing an airplane on final approach to the runway as he taxied. The pilot also stated that he heard a transmission on UNICOM but he did not understand the words. A ground witness stated that he heard three calls from N69113 on UNICOM requesting that N5500C stop. Both aircraft were substantially damaged. Both pilots said that the taxiway was too narrow for the aircraft to pass each other. The pilot of N69113 stated that he declined to taxi off the taxiway for fear of a propeller strike on the taxiway edge due to a dropoff.