I was able to get this working after some trial and error, but the client code with the previous example just plain doesn't work.
I call this in the XML datasource's load event (the rotator isn't bound to it, I'm just using it to retrieve the data), adding the same content twice so that there is more than one item:
Then I call this javascript from the client page load function:
Here's the markup for the rotator:
Make sure you have WrapFrames set to true and this should do it. I have this working off a live RSS feed.