seems to me the set of topics that need to be combined or linked are.. (probably not in the right order)
Also, lets not forgot that you can "play" midi-equipped drum machines using a keyboard (or even a windsynth!) as well as drum pads. In that sence the "drum machine" is being a "drum-synth" by not using the sequencer part. Boxes such as the Alesis D4 are "drum machines" *without* a built-in sequencer.
Well done to all the people who wrote all this i found it extremely helpful for my music project. Well Done. By the way i dont think people, like me, should be able to change the web page so easily! (I didnt change anything) i just added this. Well done anyway