Curtis at immortal hobbies sold an aftermarket apple that kinda worked with the tamiya system. It was basically a prescription pill bottle cut down and 4 IR sensors put inside. It didn't seat real well and doesn't have the 45 degree defense so your tank fodder on the battlefield. Perhaps someone knows if someone is still producing them? There is also the Impact apple but it uses a slightly different base so you can't trade it and tammy apples back and forth.