You could build the trough so that these 2U brush panels could be mounted.

[Link: pennelcomonline.com]

One thing to think about is getting at the wire behind the brush. Using these brush panels for example...once you route cable through you make it impossible to take the cover off and get at wire. The "finger duct" that the other guys linked to has a top-front cap that comes off even after cables have been routed.