Hey Steve,
Thanks for the link. Took a look and it doesn't really correspond to what I'm seeing. If I update a file over WebDAV, everything works fine (ie arbitrary tags are displayed in the share interface and in the generated website).
However, inserting anything more than simple <p/> tags and lists seems to be filtered out when I save a file through the TinyMCE editor.
Any insight into what's going on? I've searched through the code to see if somewhere tinymce's invalid elements is being set to filter stuff out but can't find anything…