Originally Posted by Veridical Fiction

Well you can go that route, or for a lot cheaper, get the M-Audio Trigger Finger which has pads and everything you need to control (via MIDI) a software sampler like NI's Kontakt.

But if you did end up getting a hardware sampler, make sure to get one that has a tap-tempo so you won't have to worry about click tracks and all that. It would just be up to the FX/samples guy to rhythmically tap the tempo in before triggering the loops.