If you want a plastic plate that is configured like a standard backplate, look at the Kydex plates from Deep Sea Supply. The Kydex is extremely strong and somewhat flexible, so it's unlikely to break when stressed. I've been diving my Kydex plate (with doubles, in caves) for five or six years now, with no issues whatsoever. The plate is standard camband slots, so you can put two cambands on it for single tank diving, but also has holes for doubles hardware. It's considerably more expensive than the plastic plate, but I suspect far more durable.