Binding to a physical interface is required if any of your apps will share port numbers on a host. If you don't have network ACLs that control traffic between VLANs, and you have a discovery service to manage rendezvous, then maybe you can get away without it. But many of us cannot.
I think that your use case is a lot more complex than ours or I'm misunderstanding some part, are you using bare metal servers in your own data center? I'm trying to grasp what's your architecture like so I can see what parallel can I make to ours.
Honestly, the only issue when it comes to image size is the initial developer pull either when they onboard to a team or when they bork their boot2docker install (which, disturbingly, happens way too often).
docker -d -p 80:8000 repo/container
It's a little overkill if you're running it on a single machine, but in a real production environment, it's a pretty lightweight solution.