Finally, someone else who sees Peter as dark-haired. Like you, my visual cues have been taken with Baynes' illustrations (so for me, Peter is dark, Edmund is blond) though of course, there is the issue of Lucy. But having Lewis be more description with the the girls, it's easier for me to move past the point where she is drawn with dark hair sometimes while others, she is blond (in the Friends of Narnia illustration in TLB for example).