I can't for the life of me find the link, but I know some people already went through and dubbed most, if not all of Final Fantasy 8. Whatever site that was hosted on also had a pretty far along WIP of FF7. If you can find it, maybe you could contact them and see if they wouldn't mind finishing up over here and letting you use what they've already recorded.
The only help I can give you is they recorded certain scenes, then dubbed over them on the video. Really wish I could find the link...