I know, this is stupid. But it only took about 10 minutes to modify the Core2duino into the Core3duino. So it would probably only take another 15 minutes to turn this into a CoreQuaduino... I'm just sayin'.
I also made this one with all the components short enough to stack an infinite number of Core'n'duino's on top. The Core2duino has been modified as a result of this.
I have not populated this board yet, but it has been etched and drilled.
Here is a few pics: