using samples is interesting because you never quite know what tuning they're in, or if they're in tune with any other samples. Then there's the fact that the futher you pitch them the more they break up and fail to hold a true note. I'm sure this explains a little bit of dubstep's dissonant elements. Grime also uses pitchbend, which sends notes wandering between intervals, coming in and out of key/true intervals. Both are deceptively avant garde i think.
but western producers usually add their western modes to samples ie they'll use commonplace western intervals to complement a melody, so they'll revert something that has been writing in another mode back to a more common mode.
But yes the pitchbend has always been quite an interesting tool, common in detroit techno as well, like an atonal wash, an inaccurate glissandi but quite often in a beautiful way.
The other thing in drum and bass is giving the drums melody, like a timpani would do in and orchestra, and of course the tuning of basslines. One thing that i always loved in detroit stuff was the melodies of the rhythm section, the way they often tuned the drums to give an actual layer of musicality, and the way the drums were so ultra rhythmic and layered, it just sounded African and bright in a way that most modern techno, minimal or whatever doesn't recognize as it's inheritance.
here is a list of modes, the ones on the top are western,
http://en.wikipedia.org/wiki/Musical_mode
and intonation
http://en.wikipedia.org/wiki/Just_intonation
whoever was talking about temperance, i think the only genuinely untempered musical culture in the west anyway is gypsy music,
http://en.wikipedia.org/wiki/Gypsy_music
which doesn't stick to any one mode. i remember a gypsy lad on the tube playing an accordion and singing and it was quite atonal, and people were telling the poor guy to shut up, even though he could clearly play and sing, it was just in a different tuning, i thought that must have been quite horrible for him really.