This may be a prototype for a mold. Yes, aluminum may be cheaper or about same price as plastic, but maybe if this is true, plastic would be poised as a "lesser" element compared to sleek aluminum. Apple doesn't need the low-end, of course. They just need the middle and/or middle-class around the world who can't afford an iPhone now. No reason to race to bottom. They do that now for laptops. Apple is doing pretty well by staying away from the low-end.