BluePhaze — Yep we leave all the objects in there. For windows 8 we wrap all the Windows 8 specific logic in an 'Is Windows 8 app' condition and put it in a separate event sheet.
Bear in mind this is only platform specific stuff, not screen size. So the Windows 8 charms, roaming data etc. For changes in screen size, we have breakpoints (not unlike media queries), where we readjust UI/zoom to work best for that resolution.
Edit -> Here's a screenshot