How about a few of these little robot buddies sitting on top of your rack, instead of in it? 1x3 passive mults with mandatory robots, and optional magnets for easy stacking/attaching.
4 channel passive multiple.
Durable plastic enclosure.
High quality gold-plated PCB-mounted jacks.
Fully serviceable (just undo two screws to access the jacks).
Optional Super strong rare-earth neodymium magnets on both sides of the enclosure. The magnets allow the hubs to be stacked or attached to metal or magnetic strips on your case. They can even attach to screws.