Cfoo (https://github.com/drrb/cfoo) is great, it's simply a yaml-to-json converter with some syntactic sugar for cloudformation. Troposphere seemed like too heavy an approach.
YMMV, but I'd much rather Cfer (https://github.com/seanedwards/cfer), which I found useful enough to contribute back to. A real DSL instead of relying on comparatively inexpressive YAML is very appealing to me.
