Many rear parts are removed when these are triked. So, trike dealers are often more then happy to get rid of and sell rear plastic. Lucky you, because in your case a trunk is not needed, and those are rarely available. I'm not sure what you mean by "written off." Does that mean it has a title that says "totaled" ??? Anything other then a clear title will greatly reduce its resale value, and make it more difficult to resell.