Designed a 30x20 cable chain for myself since the once i had on hand didn't fit and I didn't want to wait. Worked out quite well after some tuning and here it is.
You can print end parts and as many middle parts as you want. Each middle chain part is around 30mm from rotating point to rotating point. So with each chain part you'll make it 30mm longer. The ends have mounting holes for m3 screws.
There is a step file in case you need to change something for your needs. For different sizes scaling of the models should work well. Didn't test it tough.
Sadly the one down point is that the chain cant be opened at the top. So you need to pull the cables through it the whole way. Wouldn't recommend to make the chain longer than ~50cm as that will get annoying.
Takes only a few meters per part (depending on how much support you want to use). Therefore you could also use it with your last few meters from different colours and get a nicely colored chain which definitly cant be bought like this.
Printing:
The author hasn't provided the model origin yet.