Stack configuration templates
Allow for a stack's configuration to be saved into a template and for stacks to be created from those templates.
One potential use is turning up and tearing down staging environments. Bonus points for also allow a hook into your cap deploy:setup process to bootstrap additional environment-specific data (such as sample data).
It'd also be nice to be able to edit the env variables from the template before kicking off the new build.
This could also be used to implement a 'clone stack' function by optionally combining create template + create stack from template.
I know this is mentioned elsewhere, but it'd be nice to also allow automatic deleting of cloud resources when tearing down the stack. Perhaps disable auto-delete option for production stacks if necessary.
I just saw that deploy hooks are supported, so skip that part. :)