not a request yet.
I was curious if it were possible.
ll i'm saying is that the MPC can currently not do what you're asking for... you can only preview samples from within the LOAD screen, not while in the MAIN screen.
The preview function plays back the sample. So if the MPC can play a sample DIRECTLY from disc from within the LOAD screen, it should be able to do the same from within the MAIN screen, because it's the same principle.
So imagine a new ability in the JJOS: You could assign very long samples, (longer than 128MB) to an (new type) of audio track and play them back....., but you won't be able to edit these samples or use them in any other way other than playback.
This new type of audio track could be called DFD (direct from disc) audio track.
There might be one problem tho: The preview function can probably play a sample only from the beginning, if this is so then a DFD Audio track using the same principle won't be possible.