Hello guys,
however the absence of S3 backed squeeze and wheezy AMIs are a reality.
I tried to build my own AMIs using amazon ami tools but I dislike all the dependencies that need to be installed in the source instance and unavoidably are embedded in the target AMIs (haven't found a way to exclude them till now). The ephemeral storage of each instance type is not automatically mounted. Maybe I have to do something similar to what James described but outside the Cloudformation scope.
After having a little email talk with Anders, we concluded that ec2debian-build-ami cannot produce S3 backed AMIs right now, but it would be pretty straightforward to do it by using euca2ools for it and avoid installing ami tools, jre etc. I think that there is a necessity for many people to have S3 backed instances, because that poses much less dependency on Amazon services (such as EBS) and also reduces cost.
In the following days, I will try to produce instance store AMIs as Anders suggested and keep you updated. However, I believe that it is important both S3 backed and EBS backed official debian instances to exist. What do you think?