Mixer control modules in a rack? Use the 52 Series Q-Panel – 1 U high, it gives a solid housing for the modules you need to control monitoring, talkback, routers, etc. Pick the modules you want, find a free slot in a rack and your problem is solved. Also as an GPIO-extension this panel can be used.
It is up to you, whether you use the Q-Panel stand-alone or as part of a larger setup. Either way, the modules are configured the same way – using the Toolbox software.