23 Jul 10
I'm happy to say that my previous post about using a modern version of MooTools in Joomla no longer applies. With the latest update to Joomla (1.5.20) a new plugin was added, providing MooTools 1.2.4, with backwards compatibility for Joomla extensions that relied on MooTools 1.1. This update came just in time for me as I was updating a client's site from Joomla 1.0 and had a lot of Javascript to rewrite with new dependencies and conflicts to avoid.
For upgrade installs, this plugin is not be enabled by default.