You can buy a pen with a radio in it.
You can buy a pen with a MP3 palyer in it.
You can buy a pen with a video camera in it.
You can buy a pen with ...

Some battery packs has - besides the obligatory battery supervision logic - a user interface when you can press a button to see a LED bar showing the charge state.

My mobile phone doesn't just have a mobile phone. It has radio, GPS, accelerometer, dual cameras, ...

You have small environmental loggers that records temperature and/or shock and that are the size of a sugar cube. You thow it into the box before shipping and the receiver then spends 5 minutes trying to find the little bugger.

There are cabling systems where you have logic in each connector, so that you can communicate with the cable and ask it what capabilities it has.

An USB thumb can come with a very high-end cryptographic engine.

There are SD memory cards with internal GPS.

Camera lenses for SLR cameras comes with a processor that not only informs about capabilities but handles anti-shake, control of ultra-sonic motor for focusing, aperture, ...

There is an almost infinite need for smaller components, since we all the time wants more features packed into smaller enclosures.