I've been searching for a way to build my own. Turns out plain stainless mesh ain't easy to find! And the mesh drawer dividers sold at BedBath&Beyond have an epoxy coating, so they are also useless.
Finally found something, a three-level mesh office inbox at Ikea for seven bucks. They have it in colors, but they also have plain stainless. So I'm gonna use one rack as the base, and use the other two to build the 'maze' for the sawdust. Then I'll burn it in just to make sure there's no toxic coating, and then try a slab of salmon using the Weber kettle.
I'll post pics as it goes.