Apple Hardware Test for MDD G4
AHT 1.2.7:
http://download.info.apple.com/AppleHardwareTest/693-4821-A.dmg
AHT 2.0.1
http://download.info.apple.com/AppleHardwareTest/693-4817-A.dmg
I don't know if AHT 1.2.7 is intended for the 2003 MDD as well (since it's similar to the earlier FW 400 MDD), since Mactracker states that version 2.0.2 shipped with that model. From what I gather, for the 2003 MDD there was not a separate AHT disc but was rather the test was included on the 2 software install discs - but I don't have the discs myself to confirm.
MDD '03