US company Nwazet has released a whole slew of Raspberry Pi products including a $99 Raspberry Pi/OpenElec media center:

“The ‘Nwazet Pi Media Center’ is a tiny yet powerful media player, powered by a Raspberry Pi, running XBMC OpenElec. It ships as an easy to assemble kit and includes all the essentials out of the box. The kit can be secured on the back of a monitor with standard VESA 75 mounting holes.”

Nwazet – Nwazet Pi Media Center (Raspberry Pi included).

Have a browse round their site – plenty of accessories to choose from at fairly reasonable prices.