Yep, Home Depot sells metal clothes closet shelves similar to your first picture. Replaced the rear coat hanger hooks with Toyota Striker Assembly #58460-35012 (x2). Hung the rack from the striker assemblies a year ago to see if it would work (ya know just to test fit). It's still there, still haven't mounted it permanent. It hasn't moved and I only put light stuff on it. It does block a bit of the rear view mirror. I bought 18"X48" (x2), and doubled them up so I have a front lip and a rear lip to keep stuff from sliding off.
No pics, I can barely log on to the interwebs.