Apple Inc. (AAPL)’s suppliers are preparing to manufacture the company’s largest-ever iPad, with production scheduled to commence by the first quarter of next year, according to people with knowledge of the matter. Apple currently produces iPads with 9.7-inch and 7.9-inch displays. Trudy Muller, a spokeswoman for Apple, declined to comment. Apple Chief Executive Officer Tim Cook is working to shake up the iPad line.