Originally posted by vievetrick ...More important, does your son want a Pentax?
Additionally, how does the K-20 fit his hands? If the body is identical in size/shape to your K-200, you have no worries there.
When he used your camera, he took advantage of what existed. But when he gets his own, the more so since he will be using it quasi-professionally, lots of smaller details come under consideration (need to, that is). Why not forget the cultural penchant for "a surprise" and let him into the decision-making loop? Oh, yes, if he will have to go out to get that assignment somewhat without regard to the weather, you might want the lenses to be sealed as well as the body.
You will be getting him a dedicated flash and a decent tripod, won't you? As a hobbyist, he could elect not to shoot; but on assignment, things get more demanding of him. Still not as bad as for a newspaper or some other organization, but still, some pressure on him.
Just some thoughts.