Pascal Chevrel posted on twitter a link to RGraph. RGraph is cool and it's very nice and simple to use for HTML documents, but it's almost certainly not usable in XUL because it uses innerHTML and innerHTML sucks on HTML elements when the doctype of the enclosing is not HTML. I'd love to see a XUL version of that. Don't think JavaScript but think dedicated XUL elements and a few XBLs turning the subtree into a graph in a canvas element (or even better SVG). That would just rock and I'm sure a lot of XUL authors would use it almost immediately, including myself. Hey Mozilla Labs, isn't it a neat idea?-)

PS: Olivier Gambier started working on that a while ago, during his tenure at Disruptive Innovations; he did not have enough spare cycles to push it forward and moved to another job.