I bought something similar a few years ago. They were called wine diapers. They're heavy, sealable plastic with absorbent material similar to the substance found inside disposable diapers. You place the wine bottle in the bag and seal it up like a Ziploc bag. If the wine bottle breaks, the liquid gets absorbed by the "diaper" material and the plastic keeps the rest of your luggage dry.
You could probably make something similar for your beverages using a baby diaper (or two) and heavy duty freezer bags.