docs embedded in object w/ arbitrary keys?

Is there a way to use embedded docs within a object that doesn’t have predetermined keys? i.e. Rather than having a situation like this:

var myschema = new mongoose.Schema({
   field : { foo: String, bar: String }
});

Being able to say something like:

var myschema = new mongoose.Schema({
   field : { *: String }
});

Makes it a little more array like in that way - but the idea is that I don’t know the keys in advance, but I’d still like to be able to have an embedded doc.

[doneumark]

This feature is a MUST.

[raub]

@qqilihq, do implement plx, then we stop +1, kthxbye