Jason Snell is right in his analysis of a possible stylus for the iPad. It may appeal to some customers, but is likely to be an extra option and not something that the majority of iPad users would go for:
I admit that I have a difficult time ginning up enthusiasm for this particular tech unicorn. While I’m sure that artists and other pen-oriented niches would love an iPad that was better at accepting pen input, I’m not sure how large those niches really are.
Macworld UK ran an article this week discussing the possibility of a stylus with a new 12" iPad "Pro".
The article is entirely based on rumours. There is no evidence for this iPad or the stylus right now. They mention patents filed by Apple, something that is notoriously misleading as Apple file lots of these patent applications, the vast majority of which do not turn out as direct products.
But it should be noted that if Apple ever did produce a stylus, it would be no great shock, despite the article's tag line which suggests this is a change of direction to the Jobs era. Apple regularly change their mind, or more accurately, redefine an area that it had fought against. One classic example is large screen phones. Remember the iPhone 5 adverts poking fun at large screens and pointing out how our thumb reaches from "here to here"? The iPhone 5's screen size was a "dazzling display of common sense" according to the commercial, only for Apple to launch the iPhone 6 Plus two years later [Link to advert via iSpot]