Well, I think it's possible with some post if you use the Parser Code. But since the structure change from post to post, you would have to keep a monitor on you pipes and re-code it for posts with a different structure, and manually run the pipe again.
If you don't mind doing it, I could cook up the Parser Code that would work for posts with flash gallery for you. I haven't look at posts with Youtube thumbnail, so for now I really can't promise.
Best regards.