Which buttons would you use for this? Most targets don't have many spare buttons. Some (like the C200) don't even have enough buttons.
As many buttons as possible... i figure all buttons -1 to go to the menu (which would give my Sansa 6) maybe the scroll wheel could scrub a sample back and forth too.
(although you won't be able to mix the samples; that requires access to the raw PCM buffer).
I think that would be fine...
other thought: buttons should be able to be set to A. 'trigger' which starts playing upon press, and stops when clip is over - or when it or another clip is triggered --- or B. 'hold' where the clip plays for as long as the button is depressed (cheer up button

)