The joker dx11 body is kind of strange. The ankles of the dx11 body are similar to sideshow pro bodies and also early early hot toys figure bodies and also the slim African American true type from a while back. Depending on the joker shoes you would be using for this figure would depend on the body you would want. If they're the dx11 shoes you would want a dx11 body or you can bash a body to use the dx11 shoes. For this you would basically need to Frankenstein a body to some degree, which judging solely on your question, this might be somewhat advanced. If they're dx01 or the MMS joker shoes you can use really any HT narrow shoulder true type or equivalent. HT bodies are much better quality but some of the narrow shoulder bodies may be expensive because I don't think a narrow shoulder true type has been produced recently, so you might need to find a knock off true type or true similar body on ebay. The newer hot toys slim true type may work too but they don't have the dx11 ankles and the slim true type is quite short so you would probably need ankle extenders, you might as well not use the slim body. Haha If you need more help, send me a message or post any questions in the dx11 thread, I'm sure someone can help ya.
Chris