I wanted to have a place where our RPM DMX bridge and ethernet switch would be housed all together.  

Using a Keptel CG-1500 enclosure, I mounted a cheap giga-bit switch in a location where it could be accessible to connect outgoing network traffic.  Next, mount an external power supply that outputs 12 and 5 volts at 1.5 amps at the top.  This will power both the ethernet switch and the DMX board. 

After that was completed, next came the DMX bridge.  I used threaded rod, 8-32 size, and made a standoff using the mounting holes and nuts.  Attach metal strips along with nylon standoffs to the DMX bridge.  After the metal strips were set, the final nuts were tightened placing the DMX board above the giga-bit switch.  

Your milage may vary using the method above but gives an idea how to place everything in one enclosure.  Good luck and happy lighting.