All you have to do to get the tricked-out rings is buy a wide format printer, you get one free with each printer. Have to admit that was a Eureka moment for me just then, when I set up each of my last two printers I spent quite some time trying to figure out where I should have installed those white, springy things!
A friend has a wall covered with the 90 degree L brackets of the type used for supporting 12" shelves. Be bent the brackets a bit so the angle is closer to 100 degrees, then put a vertical, 2 inch bolt through the hole at the end of each bracket, keeps the spindle from rolling off. Personally, I have a taped-together stack of paper boxes, I just slide rolls (minus spindle) into one of those little cubicles when not it use.
Tried Velcro straps for a while, but now have reverted to using 11x17 nozzle-test sheets secured with low-adhesion blue masking tape.