Web-based yahoo-pipes alike plugin or app or … something

Question

I am looking for advice on how to create a drag and drop interface similar to Yahoo Pipes: dragging and dropping elements and linking them together.

I really don't care if it's Flash or JavaScript or SVG or Open Source or Commercial (although reasonably priced would be better).

Ideally I would like to describe my elements as JSON or XML and have something magically handle the rest.

Answer 1

There is the WireIt JS library: http://javascript.neyric.com/wireit/

It's quite easy to implement it, though I'm not sure if it can do all the JSON/XML magic.