^HTML will never be enabled due to the vulnerabilities it would cause. There may be a mod for vB, like MyBB, where you can use YouTube tags, but even then David might not want to have that here.
Every version does it's just automatically disabled.
And yeah i agree with muz no one is going to mind a bit of downtime if it's going to improve the forums and also it does not take that long if you do it right.
i wouldnt even say it would be allowed for them , even a harmless little bit of code could wreak havoc just opens the doorway to too many problems , and why would you want to write in html on a forum anyway ?
Exactly why David doesn't allow it. A spammer, or ticked-off member could easily use an HTML post to re-direct people who click into a thread onto a porn site or something.