It is time i finally get a bed frame, my wife and i both like this one. It looks like something i can build myself.
I would love to try building this with as few nails/screws as possible. It is for a King Sized bed.
On it's side a 2x4 is 3.5", and my robovac is 3.25 inches tall.
A 2x4 just involves the least cutting to make the part. One flush with the inside edge, one 4 inches back from the outside edge.
Otherwise a 5" tall band of 3/4" plywood can be strong enough foot, and allow almost all Roomba's to fit under it. Use three ribs to support it from inside to outside edge, save cuts by making the inside portion from the backing sheet of the boxes.