Redgate is giving out non commercial licenses for its MySQL Compare and MySQL Data Compare tool.
I've used their SQL Server Compare tools and the ToolBelt extensively many years ago, and it saved my back side time and time again.
I only happen to come across it because I was looking out for a MySQL Compare tool to work out the difference between my Test & Live Servers.
The unfortunate caveat is that it only runs on Windows ...... perhaps it will still be of use to someone.
I will try running it on Parallels and see if it can access a MySQL Instance running on the OS X Parent .... http://www.red-gate.com/products/mysql/mysql-comparison-bundle/