M.G.
I like that Elfa system you mention - I see the appeal.
My sister installed an IKEA system in a huge walk in closet off her mudroom. It holds everything from the kids's stuff, to the pet supplies to recycling. I was shocked at how nice it looked and how it's held up. Ten years later, it still looks new - and if necessary, you can just replace a piece if you had to. She hasn't needed to.
I know it's nowhere the quality - or look - but having seen how it turned out, I would consider it for kids' closets. I find when you see it in their showroom, it's loose and not installed very well (and has been manhandled). In my sister's house, it looks sturdy and attractive (or more so). Just a thought.