The Ogre CommandLineTools will convert exported .xml files to .mesh. If you have the right Blender script you should have the choice to export your object as a .xml or .scene file.
Where to dump the files is up to you, I created a new folder for those files somewhere in my (C:) drive. They do not have to be in the Blender folder. When exporting choose to export the file to where you made a new CommandLineTools folder -it's just easier to find the files afterwards- and you will have a .xml and .scene file appear in the folder, as well as images and a .materal file (if applied in Blender).
Drag the .xml file into the OgreXMLConverter application and that should convert your file to .mesh format.
I hope you find this information helpful
