First you can have a traditional in/out point loop set up. Then, you have it so there are 2 faders or pots that control in/out points within the predetermined boundaries. Make it so you can link or inverse link the in & out controls. These faders or pots would be midi assignable of course.
Another "mode" could be set up the loop duration & control the position of the loop within the sample via linked faders or pots.
Having these sort of realtime editng functions could have interesting live performance results as well as streamlined sound design & humanizing possibilities.