As Schultz would have said, "Verrry interrresting". I'm all ears for more reports.
It is difficult to isolate just one ranking factor these days, but I certainly don't rule out anything just because Google spokespeople said something in the past. If anyone has more anecdotal evidence, please share.
And if you've done some rigorous testing, we'd love to hear the details of how you tried to rule out other factors.