you can replace the 17 power supplies with a server PSU... these should all be 12v DC input with a standard 2.1x5.5MM barrel connectors...
flip them up onto their face, with the rear facing up. if you want to get fancy you could even make a base that integrates a little wedge and rod for the power button.
get at least a 24 port switch and micro ethernet cables.
this could be cleaned up to a single row on one shelf with no visible wires other than the ethernet and power lead running up and to the back. 1 switch under the machines... 1 PSU instead of 17... even one power cord...
or a little cable management at the very least...