Very neat.
You can actually push around the relative center of the loop point by setting your LFO's SHP 2 to a sine wave and setting the mix control in the area of "30". Too much and you'll lose hold of the loop endpoint altogether. Use a wave with vocals.
For example, this would loop forever unless I pushed the loop point forward with the LFO shape mix control. It really reminds me of looping on my speak and spell where I have a button that does the same loop point push function.
Here's a sample from right now. Machine stopped, just pressing the one trigger button and tweaking the LFO mix control:
http://www.allerian.com/music/MD_Vocal_Grain.mp3