WilliamCH... I am in complete agreement about the horridness of the Brothers Hildebrandt illustration of Bombadil. I would attribute half of it to the bros and half to TOlkiens description which they seemed to do fairly accurately. I have looked over the ones that you thoughtfully included as well as the ones from Bethberry.
The lego one is the least damaging on my optic nerves.
In the case of all Bombadil illustrations I think it is the song and not just the singer.