I updated my Lego NXT holonomic platform a bit. The main changes revolved around the orientation of the motors so I could get true 360 degree movement.
As you can see the motors now orient in a circle around the robot.
I tried two different mounts of the motors. A high mount, that gave good ground clearance but had less stability and a low mount, that was more stable, but required all tires/feet to be on the outside of the robot. The video below shows the differences.
Here is an example of a lower motor mount with the feet on the outside.
Another shot of the motor mounting and the feet.
I also added some cross bracing for the motors to my original triangle platform base.
Here is the video:
High-res photos are available in my Lego Mindstorms NXT Picture Gallery.