With the amount of nano and micro breweries that are starting up and looking to distribute beyond the premises, I can see several more companies springing up to offer this. For a guy that has a CDL and is owner/operator of a truck, this would make a good business.
Two different models I've seen work are one supplies just the labor and the brewery has to provide the bottles. The other one will supply the bottles/cans (you order through them). The supplier drop ships to your location, the packager shows up, does his thing, and goes to the next client.