Black Diamond Spinner leash

Black Diamond's Spinner double spring leash will do this for you. A mere 4 oz. girth-hitched to your belay loop, the Spinner has two 18 inch elastic webbings that stretch more than twice their original length and clip into the spike of your ice tools. In practice they stay pretty much out of the way, but you might want to run them inside your sternum strap to gather the slack.