... is a "Validate Embed Code" Button somewhere as a tool.

My queue is almost always full, so I can´t access the submit page with the validate button to check if the video I dug up somewhere has already been posted.

Searching does the trick as well of course, but takes a lot longer than pasting the code, realizing someone else has you beat by a few months and then riding off into the sunset leaving only a trail of upvoted dupes and a much more efficient "future posts" lists behind...

Maybe some kind of "Tools" area? Or better yet: On the "submit videos" page below where it tells you that you went over your submission quota.