I don't have any kiddies of my own, but I worked in a LHS for a few years...
I'm not sure how much things have changed (ITO kids interests) in the 5-6 years since I left the store, but I found the Academy 1/144 and 1/72 scale aircraft were great for kids about your son's age... there are minimal parts, and it tends to be fun little painting "experiment"... of course the other thing I remember was that the more guns and bombs the model had, the more popular it was amongst the "4 foot high" crowd...
As you know, kids at that age change their minds and interests on a per seconds basis :-) so I wouldn't spend too much cash on his first few kits...
I'm sure Mary (Tankysgal) will reply to this post... but her and Kevin (JackHammer81) bought one of Mary's sons the little motorised Tamiya jeep (Wild Willy - or something like that) - and he had a great time building that... In fact I seem to recall her posting pics of it here on the Big A...
HTH
Rudi






















