I went ahead and tried it. I used hard-boiled yolks, as a soft and slimy one would be not really different from making the mayo in a waterbath. It turned out to be incredibly fickle.
The first try, only yolk and oil, with immersion blender, split immediately and never recovered. The second try was supposed to incorporate the bad emulsion. I first made a paste from the yolk with a few milliliters of lemon juice and water, then started adding the bad emulsion, beating with a mixer this time. I got a thick suspension of yolk particles in oil, but it wasn't emulsified.
The third try worked at first. Again, I started with yolk and water and lemon juice, and then added the oil in really tiny amounts, half a teaspoonful at once. I used the mixer again. It emulsified, but was runny. I kept adding oil, and it was a nice emulsion, but very soft, runnier than soft peaks, like a batter. And then, one of the teaspoons of oil broke the emulsion completely :(
I don't know how the emulsion in the picture is made, maybe the sources I have heard of forget to mention that the yolk shouldn't be hard boiled (mine was longer boiled than the one in the forum picture). If this is the case, then obviously there is nothing unusual happening here - the yolk retains some of its emulsifying power even after boiling (I suppose it is the lecithine), but many of the substances which are actively helping the emulsion when heated around 70°C don't work any more. So, working with cooked yolks is possible, but much harder than the normal heated raw yolks. Which makes me think that there is no reason to try further to use cooked yolks.
I can't comment on taste, didn't try the emulsion before it split. After splitting, the yolk-containing oil is still usable as a bread dip, but doesn't taste well enough to be made on purpose.