Here's what I did.
Remington 700 with a 20" barrel. I cut down a stock to about 11" or so for my little kids. I'm in a slightly different boat in that I have 3 kids that'll be in that stock for several years. When they outgrow that stock I'll pass it down the road and put it in a McMillan for me...
I'd get him a Remington youth model and he can just stick it in a full size stock in a few years.