Fiftythree's lovely bluetooth stylus is now in Apple stores. Here in the UK I noticed they had extensive stocks of all three models last week:

We’re proud to kick off the new year with a special announcement: Pencil is now available at Apple! For the first time ever, see Pencil up close and get it at your local Apple store.

I bought the Pencil (walnut model) when it first shipped on Amazon, and though I paid a fair bit more than it currently costs I haven't regretted it for a moment. Fantastic product.