Just throwing in a quick +1 in support of this. Would be super useful! 

Working now. You have to enter the URL to the tweet to be quoted between the [twitter] tags. Example here. You have to make sure the URL is not hyperlink:

Is this any different to just pasting the normal twitter embed code into the post?

If you are not using the rich text editor it should work. But some people have problems so just use this instead.