Come up with a way to produce mobile devices that are customized to a user's needs.
People will increasingly use mobile devices for a variety of use cases, but many of these will be so specialised that existing standard devices will not be ideal for them.
Offer a variety of standard device sizes (e.g. equivalent to smartphone - ereader - tablet ...) and let users customize them in terms of
- display (epaper - cheap LCD - shiny LCD...)
- input / output (touchscreen? sound?)
- connectivity (wireless - mobile phone - none at all...)
- connections (USB - SD card - ...)
- energy source (what kind of battery? solar cells? crank?)
- Digital camera with built-in 3G to share pictures
- Smartphone with an e-paper touchscreen
- low-cost reading device - http://thewikireader.com/ is a nice device, but has been criticised for having a poor screen. Also, if it had solar cells, it would potentially be more useful in developing countries.