Hi, we thought that this may be of interested to some of you.
We just started a kickstarter for VoxCube, an 8x8x8 RGB LED cube which is compatible with Raspberry Pi and Arduino.
The Cubes are also chainable to be able to create large displays. The image below is four cubes chained together.
Here is a single cube;
Check out the video on our Kickstarter page;
https://www.kickstarter.com/projects/2135028730/voxcube-8x8x8-rgb-led-chainable-cubes