Random half-formed idea time. Thinking about marking up an article (e.g., from PLoS) with a phylogeny (such as the image below, see doi:10.1371/journal.pone.0001109.g001), I keep hitting the fact that existing web-based tree viewers are, in general, crap. Given that a PLoS article is an XML document, it would be great if the tree diagram was itself XML, in particular SVG.