Clark's makes narrow boy's shoes. Not cheap, but they do have them.
I got Matthew a whole bunch of shoes there in various sizes with that gift card I won.
FYI: Their sizing is British, so what is labelled is a half size smaller than what it would be in the US. EX: a shoe labelled 10.5 would be a US size 11.
Re: Cleo
Good to know. I'll have to see if there are any stores around here that carry Clarks in children's sizes.