I hope to make something like these myself. The Thornes ones look like stainless, but I hope to use either flat galvanised strip or aluminium angle section with about an inch cut from one side at the end which would overlap the outside end of the floor. Drill two holes in the overlapped end to attach with screws.
Seems we have to face criticism on every post, so here's my reason.....
I want a landing board on at least one of my hives simply because I like watch the bees come and go and they easier to see, video and photograph. I can spot the pollen easier and also get a better look at what they throw out of the hive, before it falls on the ground.