Multiholder - Prototyping Board for the Arduino and Rasperry Pi (also fits the Pibow)
Taking inspiration from Oomlout's Arduino Holder (http://www.thingiverse.com/thing:716) we added some extra real estate around the board and put in some extra holes to allow you to orient the Arduino either way, then we added some more holes for the Raspberry Pi and even more so you can replace the bottom plate on your Pibow!
This ships with all the hardware to attach an Arduino or Raspbery Pi (Arduino NOT included folks!), a 400 point breadboard and some sticky feet to complete the look. For the Pibow, use the nuts you already have!
N.B. some of the images show boards we custom cut for the Nottingham Hackspace. If you want some custom boards we'll need a minimum order of four and a copy of your logo. We will do the design work for free as long as you promise to tweet about it (or facebook or G+ or something).