Ok I looked over the forums and didn't really see anything definitive on whether doing foreign SEO, submitting your English site to foreign directories, whether left in English or translated by altavista, will help your traffic. Will you gain in SERPS for English Google or only for the country the directory is for, i.e. Russian. Obviously the traffic isn't going to be as quality if your targeting a different language but some may speak English and be interested right? Anyone with experience SEOing their English based site to foreign directories please shed some light on this. If it helps I can see myself submitting to all the foreign directories as I have exhausted the english speaking ones.
One of my blog is hit by many international Googles (beside the .com) but not even a single traffic from the .com although I'm using English language. I've not submitted to directories though. I'm not really sure your definition of how many is "exhausted". However if you really have submitted to tons of directories and still got no great traffic, then the problem might be on the site itself (design or seo) and submitting to another tons of directories won't help much imo.