Beaterator offers a range of tools which have been previously unavailable to mere mortals including, "8 tracks of sequencing, 4 tracks of original loop crafting down to the 16th note, 240 bar limit, full BPM control, ability to upload your own samples, an advanced effects module, original sound bank comprised of hundreds of loops, drum kit sounds, synth and string stabs and more provided by production gurus Steinski, Matthew Dear, Juan Atkins, Avee & 3D and King Britt".
http://www.beaterator.com/
tis free.