I don't have plans to translate the plugin to other languages as I'm really just wrapping the existing sevenup scripts. Maybe try right at the sevenup project site? Try code.google.com/p/sevenup/
You could create your own translations by simply editing the .js files installed to /plugins/system/sevenup
The js files are minified, so you might want to try using jsbeautifier.com to reformat the files so they are more readable.