What a nice idea to design a phone that let you choose what you want to equip.

Using the jacket-buttons, you are basically able to snap the module you need, for example the master unit with a camera accessories. When you feel like to bring a QWERTY keyboard, just bring along the keyboard module and snap it on!

From the description,

Carrying mobile phone, digital camera, and MP3-player is bulky, heavy, and expensive. The thesis project me-mo is a concept that marries several portable electronic consumer products into a modular system. The modular design offers among others mobile phone, GPS, and camera to take advantage of each other's qualities to create new interesting functions.

Source via techeblog.com