A company called Cideko has built a wireless keyboard that includes an accelerometer, enabling you to wave it around and use it like a mouse. It's aimed at people with a laptop or nettop plugged into a TV.
It functions fully as a regular 80-key QWERTY keyboard, but if you tilt it to the left, right, forward or backwards, then your mouse pointer will go left, right, up or down respectively. It's a solution that keeps you from having to deal with an iffy trackball or a separate mouse, in the occasional situation when you need a keyboard/mouse plugged in.
It connects through a USB dongle, and works with Windows, Mac, Linux and PS3. It's powered by a pair of AA batteries, which gives it about 50 hours of battery life, and will switch to a power-saving mode after it's been idle for 10 seconds. It has a range of 50 metres, though that'll reduce if it has to go through walls or floors. It costs either £70 from Cutebitz, or Firebox and it's available now.