Easiest way to do it would be to grab some of those horizontal lacer bars from Middle Atlantic. They are screwed in via one hole, and go out up to 6" away from the rack rail. That way, you can dress the cables by velcro-tying them to the bar, so you don't have a big ball at the ends of the module.
These things:
http://middleatlantic.com/rackac/cablem/cablem.htm#hlbars
These things:
http://middleatlantic.com/rackac/cablem/cablem.htm#hlbars
