Forgot to report back that we did get the little wire mail/key rack installed on the door. Trying to get DH in the habit of using it.
I saw a fancy double-decker boot tray in a catalog and started looking for a less expensive version for our tiny space. I looked in several stores and couldn't find anything like it.
Then I remembered a set of plastic shelves that I had disassembled because they weren't sturdy enough for where I was using them. (Also, I hadn't decided where to move them so had been walking past them long enough that they'd become invisible. )
I assembled half of the shelving unit and turned it upside down. That turned the shelves into a double-decker tray. The sides of the "trays" are about 2 inches high. My snow boots stay upright and corraled on the bottom tray instead of falling over and oozing out in front of the door. The top tray currently has my bag of clothespins (hope to get back to drying laundry outside some day) and a water jug we use to give the outdoors cats their water.
Useful, takes minimal space, and free!