A Tamiya TLT-1
In stock form they are not too quick - Not the best performers either to be honest (locking the center diff does help). However, they seem to be available VERY cheaply recently - for as little as 75 euros NIB! In stock form they are a good car for someone new to RC I think and can be set up to be run in 2WS and 4WS with the parts included in the kit. The axles are pretty compact and tough I think, so when he grows up you can convert it to a crawler, make or buy a custom chassis for it
A custom chassis like
this perhaps? Traxxas 1/16 gearbox for lower CoG and slipper clutch (and a center diff as a setup option), 3000+kv brushless, room for a good stick pack LiPo and an overall scale appearance by usig an extended wheelbase, Tamiya Wild Willy 2 tires and an HPI Wheely King body. It goes like stink (
here is a video with the original chassis but same electronics running on snow and ice), especially with the new chassis it is a lot more stable and the drivetrain should be up to the abuse now.