Apple bought P.A. Semi for a reason...
Think about it. In April of last year, Apple purchased P.A. Semiconductor, a manufacturer of Alpha and StrongARM type processors. Figuring that the cycle to retool this company, design and manufacture completely proprietary chips JUST FOR THEIR OWN DEVICES will likely take at least 1 1/2 years. That places the first Apple designed chips from P.A. Semi being available roughly later this year, but probably not in time for this current batch of iPhone 3G S⃣ phones that are coming next week.
Maybe I am way off base here, but I would expect a revolutionary device by the summer of next year. They can make it smaller, more efficient and faster by combining as many different chips as possible into one. At that point, they wouldn't be grabbing as many parts off the shelves because they might be using a single proprietary chip that integrates many different chips... that is only available to them.