I set up the exceptions in the Config tab to load a different theme for mobile devices and I would really love it if I could set a different home page also. I would like mobile visitors to see completely different content than desktop visitors. Is there a way to do this?
If your current theme is responsive then you can use media queries in the custom xml layout update of your home page depending on how different you want the theme to be. You might try using static blocks to display your home page content then and having a 'mobile' static block then an alternative 'desktop' static block that displays over 'X' pixel value.
If your layout is set to full width then you don't have to worry about the left or right sidebars. Otherwise just correspond your media query break to the 'no display' function of your sidebars and the mobile static block will be displayed at the same break point as your hiding of the sidebars.
Hope this helps.