I know the problem. I have some nice DVDs of Mexican movies in Spanish (I prefer) but without any subs or dubbing, like "La casa del terror", "Frankenstein, el vampiro y compania", "Ladron de cadaveres"... it's always a little frustrating.
In the same time some video companies from Thailand, Mexico, and even Cambodia are starting to release some of their national movies with removable English subs, so we can maybe hope a generalization of the process. In fact, even an English-speaking movie subtitled in English can help foreign people to fully understand a movie (it's my case).