I finally received a response from Tascam and stantheman was right. Here is their answers to several of my questions concerning the DR-2d, DR-100 and DP--008;
"The DR-2d is equipped with cardioid microphones and has a battery life of approximately six hours.The built-in microphones have three gain stages and are configured differently than the DP-008 microphones. There is not a performance comparison available for these models.The DR-2d is equipped with an auto gain feature and low cut filters for the built-in microphones to assist in capturing a quality recording.The DR-100 is capable of selecting either line input, XLR inputs or the built-in microphones as a source. Two sources cannot be combined while recording."
So the the DR-2d is in fact cardioid!!!!