MySQL Proxy 0.8.0 has been released at http://dev.mysql.com/downloads/mysql-proxy/
While it took a while to get it out, it contains a lot of good stuff and will make a few more things possible for the future. First of all, it is the first release with a threaded network-backend allowing to use plenty of CPUs.
The other big infrastructure change is mostly for developers: out-of-tree plugins can now be written. Now you can write plugins for the MySQL Proxy against a installed MySQL Proxy. No need to have the MySQL Proxy’s source code around.