I was trying to create a stretchy arm rig that still used the IK set up. And this is the best that i could set up. right now only the forearm stretches when i pull the IK out past the original bones limit. But i made a bone at the elbow that can be used to edit the length of the two bones. Kind hard to explain but i'll include the files if anyone is interested.
https://www.dropbox.com/sh/96iqvgaq8oy3239/AAAAclbBYwy2PrSf3zEMP3cra?dl=0