Under Bed Storage

I saw this wheeled under bed storage while in Germany. I liked two features of this set-up: It is lower to the ground and it is a much more stable system. The bars provide extra support for the plywood bottom and I could make the bottom much thinner and the overall storage system much lighter by not having to provide a sufficiently thick bottom that supports the typical caster wheel attachments.

I was not able to find the bars in Germany or in the US, hence, I built them myself. They are made from 1" square aluminium tubing and 1 1/8" casters.