I'm currently working on a plugin to work alongside qTranslate, to disable it for particular sections of a site, and to control which languages apply to which sections.
The plugin as it stand is here: http://sltaylor.co.uk/wordpress/plugins/qtranslate-selective/
However, it's not working properly yet. If you're interested, please read about it at the above page, download it, check it out, let me know if you make progress (or have already solved this issue yourself!).