There may be some plugins for that, the other solution is a second WordPress install in a sub folder or sub domain and the menu going to that page.
But you may want to explain exactly why you think you need another theme for that page, as there may be an alternate solution to that.
You can override any of Xtreme styling options at the page level with Custom CSS, and you can implement any of its insertion area at the page level. You also have a number of page options to change the layout of any specific page.
So you can make any page look completely different from the others with Xtreme only.