We have open-sourced our backup tool for SVN repositories and MySQL databases. It's called Mango Backup.
Mango Backup is a backup tool for storing backup copies of your SVN repositories and databases onto Rackspace Cloud Files, one of the best cloud storage available in the market. Currently, Mango Backup supports MySQL databases.
It is built using Zend framework and OpenCloud Files API from Rackspace. You will need an account from Rackspace Cloud Files to use it. This project was created as part of backing up our own projects at www.syncrelease.com
Currently it is hosted on Google Projects website, please checkout and download to start using it: