(Image credit: Future) By now, rumours of a folding iPhone are reaching fever pitch, with the premium device set to arrive in September this year. It could be the first significant new product announced by new CEO John Ternus, but new reports suggest Ternus himself has been working on another, even weirder, design – one that I can't see hitting our best iPad for drawing roundup. According to Macworld , one of Ternus' "pet projects' over the last few years has been a giant folding iPad – one with a whopping 18-inch display. Which, for my money, sounds like something we just don't need. A folding iPhone has been rumoured for years, but do we really need a folding iPad? (Image credit: foldable.news) In Apple leaker Mark Gurman's Power On newsletter, he describes how “a gigantic, foldable iPad” with a “a Mac-sized giant screen" is in development, but there's no guarantee it'll ever actually see the light of day. Article continues below This isn't first time we've heard rumours of a folding iPad.…