I'm just not sure if it's a good idea to make one that's so dedicated to a single site in principle. But yes, I can probably implement something like that without too much effort, using the VIDEO name for future purposes but only YouTube support for now. There are various ones that automatically embed if you paste a link like http://www.youtube.com/watch?v=Q8y8Yab9vlQ but I think that's just annoying.
My Opera works like this:
[VIDEO=http://www.youtube.com/watch?v=Q8y8Yab9vlQ width=620 height=375][/VIDEO]
But this forum works like this:
[video=620,375]http://www.youtube.com/watch?v=Q8y8Yab9vlQ[/video]
or this:
[video width=620 height=375]http://www.youtube.com/watch?v=Q8y8Yab9vlQ[/video]
I'm not sure why it's internally inconsistent like that. I'm leaning toward implementing the latter. Any preferences?