Hey marcus, based on my quick experience tweaking EM code, my guess on this issue would be that the real problem lies around not calling proper WP hooks during EM objects initialization.
For example, on EM_Event you do the following:
$this->event_name = $event_post->post_title;
$this->event_owner = $event_post->post_author;
$this->post_content = $event_post->post_content;
But doesn't call the filters that WP calls on these attributes when it's initializing a "normal" post (by instance: the_title, the_author, the_content).
Although i haven't tested this idea, if i'm correct, this fix would not only fix the issues with qTranslate, but turn your plugin compatible with any other plugin that operates through these hooks.
Have you already thought about this?
(just reminding you that this is only a guess based on my limited view of the code, maybe i'm just saying nonsense things here =p)