There are some Japanese people carriers that have a tilted rear mirror on the door pointing downwards; the same idea as a passenger door mirror on the big trucks so they can see the kerb I guess.
My ladders hardly even come off the van and I have a strict procedure of 'throwing' the ladders up onto the roof rack when I've done and clamping them at the same time - I will not be stopped midway through that procedure.
In the trad days I forgot to secure the ladders on several occassions, but thankfully I got away with it both times. Being trad I guess having a special mirror focused on the ladder is a good idea.