I did a search for this in several places but came up empty.
If it isn't too dumb of a question

EA-1
ER-1
ES-1
EM-1
EA-1 - mk II
ER-1 - mk II
ES-1 - mk II
ESX
EMX
I know basically the ER is more for percussion, and the ES/ESX is for samples, and I think EA+ER = EM, but to compare polyphony, etc. a chart would be really cool. Can all of the above be used to trigger external synth sounds (not necessarily drums) through MIDI? Can all of the above be used to trigger external drum sounds through MIDI?