When I first got my Raspberry Pi I was measuring it and modeling up a holder for it. I'd been thinking about it for some time and wanted to get my hands on one before I started making it. This is the 3rd iteration of the design. I added the cut outs and shaped the stands to provide better clearance and hold the board more securly. Enjoy!
Print it and snap the Raspberry Pi board into the holder. Make sure you have the board in the correct orientation, the sides are marked USB and SD-Card corrosponding to the two ends of the board. There are four 3mm screw holes for mounting it into a larger case.