yeah man , the simult thing would work, i suppose it'll save time if you use the undo seq to copy the relevant simult pad across loads of pads. otherwise it would just be gpe>simult>assign to pad x Vs window on out note>change out note to note x
regarding the potential of simult i posted about mpc macros here back in april :
viewtopic.php?f=25&t=142497&hilit=macrosthe things ive used it for are mainly for assigning track mutes/solos to pads or quicker navigation through the mpc when playing live. e.g you set up a pad to trigger a string of simult notes that helps you switch mpc settings or the highlighted field but yeah would be interesting to see what musical possibilities are there too.
One thing that has the potential to be even more powerful for this is the new pattern mode, ive tried it a little and it works beautifully for this type of thing. Im going to do a bit more experimenting and post some examples in a few days.