For what it's worth, there is a complementary (early stage) project a colleague of mine is working on where the idea is to let you leverage cloud formation from the command line and get closer to what you're talking about (deployment of a more complex infrastructure rather than just a single instance):
This looks nice. I'm currently in the process of creating a deployment script to cluster out wowza media server with a edge/origin setup ,auto scaling and loadbalancer setup. Really wish beanstalk was less error prone and worked 100% of the time.BTW does anyone know if beanstalk supports paid Ami's ?
https://github.com/mozilla/awsboxen