I can't claim to have come up with this but i thought that this is a great idea.
Use two Weber warming racks (crescent) and an 18" circle grid from an 18" Weber. Place the two warming racks on the main grid, spaced apart, and fit the 18" grid onto them to fit snug. This is sturdy and solid and you can use it to cook chicken and burgers away from the flames to reduce burning and slow down the cooking. This setup also fits under the closed Weber lid.
Here are some pic's of it.