So often, children's furniture is particle board crap that barely lasts long enough for the kid to outgrow it; that's what happens when you try to put screws into mush. But if you pay a lot for something that lasts, what if it is no longer an appropriate design? In Japan, you can buy this cabinet called TREE, which has a clever solid ash leg design that lets you stack one unit on top of another.
The units are built of solid white ash, and look like they are built to last. (and at 81,900 yen each, about a thousand bucks, they better). I don't think they are necessarily only for kids, it is a good idea for anyone.