My first try with OpenScad, the box is fully customizable. I hope you will enjoy with it, and show us many boxes made with.
If you play with the Round value you will go from the sharp to the round sides box If you want a chanfered box, set Resolution to 1.
To export each single pieces, just set the other to "NO" value. The Top and Bottom Shells are the same, so it's not necessary to export them two times.
Check the animation below to see how to setup your own box.
You can change the text shape with any font listed here .
Have fun ;)
Edit: Feb 12 2016 - Minor bug fixed on unaligned hole when using more than 2mm thickness