OK. I found it! I seen it on an ebay auction. Unfortunately it is a whole truck they are selling, but you get an idea what the rollcage looks like. It looks to be a very strong rollcage and fits under the stock body.

Check out Ebay item 6009689867

Edit - Sorry, my eyes are not very good tonight. The stock body is cut so the back of the rollcage will fit. But, the right body should fit over the rollcage.