jimbeetle - 3:09 pm on Dec 2, 2010 (gmt 0)
I've had one instance where tweets helped rank a page of mine.
Sorry in advance, I can't find my bookmark to it at the moment.
Somebody did a nicely controlled test a few months ago that showed tweeting a new post or page drastically cut down on the time it took for Googlebot to visit the page (the number I remember is 80 seconds), and also the time it took to appear in the index.
And your other observations about Twitter authority, etc., tie in perfectly with what Google passed on in Danny's article.