I went to Universal Studios Hollywood this past Saturday, and of course I took the backlot tour. We passed through their "greenery" area, which had several large props sitting on the side of the road. They were mostly items being used for a new 'The Fast and the Furious' attraction they're building ... but there, on the left-hand side of the tram, sat the Mule from 'Serenity'. It had a little sign on it and everything. Unfortunately, I was unable to take a picture of it, but if you're in the area and you want to see it, it's there - at least for right now!