Thanks Aquinas. I think this answers my question in the way I was wondering about. I appreciate everyone's anecdotal evidence, though I was looking for the bigger picture. I know that there is a huge range of normal and no one experience proves the rule. I just wondered what the connection was in Ruff LOG with these early very physical traits and intelligence. But it clicks for me hearing that intelligence can, but not always, leads these kids to physically seek more. Thanks.
If you are interested in speculation, I would guess that timing of physical milestones is related to temperament, environment and parental involvement and the same environmental and parental involvement factors (as well as good overall health) that link SES to IQ probably link SES to early walking. However, there's such a big range of normal for walking (8-20 months) that I'm sure most kids who walk early won't be gifted, and of course you can be a late walker and have a high IQ.
Also, for many typically developing children there is a plateau in language acquisition while the child is learning to walk. Assuming this shows that learning to walk and certain stages of language acquisition are competing processes that can slow each other down, it's possible that gifted children who acquire language more rapidly better clear the way for early walking by reducing this competing process at an earlier age.