What other interests do they have? Maybe you can also incorporate something else they like into the design. Generally kids especially at that young age often appreciate some sort of personalization that makes a gift "theirs"... Whether it's a picture or artwork of something they like or their name engraved. I notice this especially in kids with siblings. Whether it's because they always have to share their things or someone always gets hand-me-downs, lots of times I've seen kids get presents where their favorite thing about it is that it had their name on it. That said, in terms of recommendations, I would suggest either a simple two handed lockback for a folder (whatever is easiest for young hands to manipulate) or a railroad spike knife because of the shear novelty and coolness factor. Kids don't always appreciate practicality, so I wouldn't necessarily go hi-tech or anything.