I've got up to 15 Homaco black powdercoated aluminum 4-post racks for sale.
Racks are adjustable in depth up to about 24", and can optionally include similarly adjustable shelves.
These were recovered from a demolition job when a large telecom company vacated a whole bunch of office space (yay layoffs!)
I'm willing to let them go cheap. I'll post pictures as soon as I get one put together and a picture taken.
Pic from Homaco's website for this item: