I saw FunFunBoys runner stands, and thought i could use a couple, but i wanted a semi-clean way to store them when not in use. This is the first thing i came up with lol.

They're meant to stack opposite of the previous stand. So one that is right side up, and then an upside down one, and so on. The single should fit 10 this way, and the double should of course then fit 20. 

Here's a link to FunFunBoy's model: Gunpla Runner Vertical Stand