@thomas: there is NO LATENCY ... with a good hardware sequencer, you never have to change buffer settings or worry about cpu lags that you have to care about while using a desktop pc or laptop. And it will NEVER crash, i had a Akai MPC 2KXL and now the MV8000 and have played dozens of live giks, they never let me down
in fact of course even a hardware sequencer has latency and it can crash, too. Think of it like when a pc has a chance of 15-60% (depending on the hardware, the os, pc or mac ...aso) to crash or to have really bad latency lags a well done hardware seuquencer has not even 1%.
@IamEvil: like Nike said: just do it
it will give you more than you can expect ... the MVs are amazing machines the samplimg engine is genious even if it hasent's Rolands VariPhrase tech ! Needless to say the MVs are the only hardware sequencers with VGA option and mouse-editing in real time on the whole planet
google for some reviews or get yourself a pdf manual an look for the pictures and describtions of the sample editing and modulation features, i think it will do more than fulfill your needs !