People are buying styli. The Kagi Stylus is popular on the train I ride to work. I saw someone using one on their ipad with Notable and I asked her where she got it (it has a clear disk on the end so it feels more precise) and she said ebay. Right from China to your mailbox. But it turns out that this type of styli is hard to come by otherwise. In my email exchanges with the vendor they claimed they were selling thousands of them, but I would not expect them to say 'hardly any' so its not solid data, Ebay's 'how many are left' on their buy it now auctions were starting at 100 and working their way down to 0 pretty quickly (a few days).
That said, one of the things I really liked about the iREX Illiad (RIP) is that it used an honest to god Wacom stylus digitizer. That can capture tilt, pressure, and doesn't require a conductive connection between your finger and the tip. I've argued for a while that blending the two would provide a really useful combination.
The Wacom only allowed single touch so using capacitive touch as 'modifier' keys would allow for combined intent+action type things.