i must say i like the "stang", here in the south US they are still plentiful $$$
but readily available, a fixer upper can start @ 3000+ and run to 20.000+
finished saw maybe 30 to 40 at a local car show in november,
i was going to comment on wire, we have the situation where on e guy will move anothers extension and compressed air cables and hoses, we have small 1/8" compressed air in many of the machines for various actuated task.
all off these are secured with cable straps, some have a slice of bicycle tire rubber tube with an extra inch or two of cable between the straps, this takes the impact of a small pull but will not keep cable from severing if some one trips over it (depends on strength of cable) as for what i see on yours, i would mount cable tie to secure connection then slit a piece of pvc (to get cable in with out removing ends and build a housing for hand held controller.
i'll show photo of my zero mount on another computer oh an i got one guy in my shop who loves making items like your bit holder hes got a roll around box for all tools, some tools have thier own like the moulders, saws etc. he also marks all bolts and hex heads with a sharpie marker as to what they are at thier location so he no one who has to work on machines has to guess what wrench to use
cabnet