Hi that tool sounds great, probably has a lot to do with the amen break being one of the most sliced up breaks ever. I have a couple of tools that do a similar thing called X-Incarn,brilliant if i might add,
more tools would be wave surgeon and also recycle, they do the same thing, loop slicing.
Though where single hit drum loops are concerned, which i assume you are constructing judging by your first post then you can do a similar thing right in your sequencer by chopping up your drum parts.
the velocity cut of thing irie is talking about is a fantastic and creative way to make fills, or variations in the beat. If your sampler has a filter then you should be able to assign the velocity to the filter so when you hit your keys harder they have more cut-off and when you hit them softer they have less cut-off and vice versa , on a good sampler this feature of assigning the velocity to a parameter can be done to practically anything, pitch, start point (see below), filter, resonance, even the amount of lfo to send.
I use halion and that has a sample start point that can be assigned to the velocity so depending on how hard i hit my keys the sound will be triggered at relational start point. This can also be used creatively for fills.
another creative fill would be to pitch the drums. like a snare roll descending in pitch.
for maximium drum and bass fillage I recommend aphex twins new album and also squarepusher and aquasky.
as for a melody, well in drum and bass it seems that nice fading LFO lazor zaps and big bass is certainly kool. sometimes its just best to play a creative game of question and answer with some really big sounds and noises.
Imagine a blues jam where everyone playing is an alien with an individual voice in some inteligent rythmatic conversation that compliment the beat in radical ways in the fill parts, you can catch people out when your chucking sounds at them in an almost expected manner and by doing something just slightly different each time can often cause spine tingling attacks on your sonic receptors.
I often imagine my music, escpecially the drum and bass as a sonic assault of sounds that are aware of each other and give each other space to breath, then team together for the occasional strike.
I hope that wasnt to deep!
oh and remember, to many fills can seem like your trying to hard, its not worth doing a fill for a snare roll if it doesnt catch the user out or if it doesnt create any energy, you could put a fill at the end of each 2 bars but as soon as it becomes obvious to you whats about to happen then thats the point of boredom - but i wouldnt take this point to seriously as it comes with listening to the same beat over and over and over and arrrgh!
let your fills catch the listener out. so more variation in the beat and quantising will really give movement and energy to the beat, then the fills are just an extra added bonus
regards
fluxtah
http://www.mp3.com/dafluxtah