using a smpler for live performance

here's my situation. guitar-bass-drums band using keyboard keys taped down during live shows and stepping on A/B boxes to cue them on and off during songs.
would like to stop carrying around three keyboards and dealing w/ crackling sounds generated by current system. we would like to sample the tones (and some drum loops) into one sampler and use it to cue sounds on/off during performance. what are our possibilities? keep in mind foot swithes would be best for guitar players to hit for cueing sounds?

thank you