A comprehensive and (hopefully) simple fully parametric ball bearing generator.
You can change things like height, radius, spacing, hole type, hole size, ball number, etc., and remove sharp and hard to print edges using the debur parameter.
Also, it may be a good idea to turn the Definition parameter down a bit when using a large amount of balls. If you dislike using Customizer, just download the OpenSCAD file. Requires http://www.openscad.org/downloads.html. Feel free to request for any improvements.
A similarly minded script: http://www.thingiverse.com/thing:606588
Just edit, export and print.
Supports should be used if Custom_Height_Toggle is left on.