as far as the basic channel sound goes, I spent a little while trying to figure some of it out.
The element that really intrigued me was the 'dubchord', though obviously their appeal extends way beyond just this one method.
Anyhow, apparently there are many ways to make it, where the general rule seems to be to take a variably rich sound and put it through some effects (duh).
Specifically, you can do quite well with a couple of slightly detuned saw waves playing some kind of chord which is then low pass filtered to taste (with movement on filter cutoff frequency being pretty crucial) and then fed through delay/reverb/phaser/chorous in any order that you like (again, indtroducing some movement in the sound here is pretty key I think, eg more filter movement, changing delay times etc etc).
not ideal but it's definitely a workable starting point. If you have Reaktor and the Electronic Instruments 2 collection, 'Akkord' seems to do a very nice job in this vein actually, via a different method of synthesis, but built around pretty much the same principles.