Pause sample on 0B02, 0B01 to continue. Maybe 0B03 for rewind sample to zero? What do you guys think?
Yeah!
B1X slide pitch to 100% forward with speed X, B2X slide ptich to 100% backward with speed X 
plus a command to set the offset while playing (or breaking old songs and changing the 9XX to do that?)
We just have the slide commands for that (010x / 020x / 05xx) and you can combine this with the 09xx effect. Though not for individual notes if you want to do chords and only affect one of the notes.
Stopping and resuming can be done a similar way by combining commands.
you can now use the 09xx command in combination with B1 command on the panning/volume column to reverse play your sample from a different offset than from the end.
For small samples this is pretty doable, for larger samples this is cumbersome at the moment.
A b03 command for full rewind is overkill because just replaying the instrument by triggering a new note plays the sample from start.
If implementation of the 09xx commands being attached to user settable node-points in the sample editor will actually being done, you can set your own offsets and then use the 9xx and 9xx and the bx combo to start stop the sample from any programmable position (256 in total) you actually like.
Oops…
That sounds really nice, I was reading about that before and it would be great if that happened. But there’s still room in the 0Bxx command to be used too. Seems to me like a nice little addition.