Not as far as I'm aware, nope; the poll feature is an add-on to threads, so the latter has to exist for the former to be used.
That doesn't mean you have to put something of substance in your post when you post the thread, though. You can just have the body of your post be the question you enter in the poll. It's about as close as you can come to having a poll without a thread.
Hmm... I just thought maybe on the front page where all of the different topics are listed there could be one for polls on their own. And you know how some forums have a poll of the week on the side of the screen? Just a random and fun little question? I don't know. Just popping out ideas. I really like the polls.
Well, if you wanted to take a poll on a highly controversial topic, without everyone arguing and have it be necessary for the staff to close the thread.
There was a thread about religion a while ago where the OP asked people just vote. He requested that people not explain their answer, or even say what their answer was. And people respected that. The one problem was that without people posting, the thread risked falling of the first page of the forum pretty quickly, so people took to posting just to say, "I voted." That way the thread stayed where people would see it for a normal duration. You could make the same request, and I think people will still respect it.