I could quote Frank's response to Sebastian, but I won't. The question lingers, however, as to whether we view xml as off topic here. On the one hand, xmltex is something that runs through LaTeX, and, on the other hand, if xml is a presence, it changes the package writing scene inasmuch as some of the things that people get from packages can be provided (sometimes better) before regular LaTeX action begins. I know that there were lots of bad early experiences that some had with sgml. It need not be that way. -- Bill