[l0ner]

What comes to my mind is the Eclipse Modeling Framework. It's not exactly light-weight, but it always worked pretty well for my use cases. Throw a model at it (XML schema, annotated Java, ...) and it generates a Java implementation including a tree-based editor; certainly good enough for prototyping purposes.

[jventura]

I'm curious about your use cases, as I do not seem to find much information about model-driven development out there. Can you elaborate a little bit more about what you do with EMF?

I'm asking this on the perspective of someone who is about to teach model-driven software engineering for a semester but cannot find much pratical use for it..