I've added an image tag in my XML, for the libraries where I have a photo of the hardware or screenshot of the library example actually running. The intention is to allow Ardulibrary or any other library browsing tool to give the user nice visual impressions of the libraries, especially what hardware they actually use, which often can't be communicated well in short descriptions.
Here's the XML again:
http://www.pjrc.com/teensy/td_libs.xml
I've pretty much just made up a few tags... feedback is most welcome. If you need me to adapt my XML for Adulibrary, just let me know what you need and I'll try to incorporate it. Or if anyone else wants to use the XML and needs the format altered, just let me know and I'll do what I can.