Is there a YAML Database?

I like YAML's data model a lot, preserving most of the simplicity of JSON and extending it with a few sometimes-important features like custom data types and references.

So is there any way to store a lot of data in the YAML data model (or something very similar) and query it using an index? Like a YAML database, analogous to XML databases or JSON databases like Mongo DB. Or is there a mapper from YAML to something like Mongo DB that lets me transparently use it as a YAML store?

I haven't found anything so maybe there aren't any. Why would that be? Is it a stupid idea or is YAML simply too young and they will come?