Generic rackmount cable management arm?

[SiegeTheDay]

This question is aimed at people with home rackmount cases, Norco, etc. Or to admins with older rackmounted hardware at work that didn't come with a cable management arm. I fall into both categories.

Have you ever seen a readily available solution to add an arm where one wasn't meant to go?

I have obtained a few older arms and have a few ideas to mod, but if there's something available that is a known solution, I would love to hear about it.