my god son is about 8 now. He is fan of Sponge Bob.
Designing a sleeveless for him is one of my next target. it will just be the “person of” sponge bob.
but I see the issue with desiging patterns with cartoon figures if you want to make them available and maybe even for sale… I would not sell them then.
so, since that is out of the line… I think 7 yo are not soooo much into the tractor / car / toy thing, but yet they are… they already want to feel cool, but they are still kids… I like the tractor scarf. Just maybe for kids a little younger (5-6 maybe) - or devoted to tractors!
the kangaroo pouch is definitely great. The hoodie, too. But then it is hard to come up with something new… yet even “already known” can be done well, of course.
I would think of “funny” designs… how about a train shooting out of a tunnel? with extreme perspective? and at the back, the train goes into the tunnel?
or a worm eating through the pullover, sticking out in a few places and having tail and head visible? you could incorporate cable design there.
for a winter design, I could see a mountain landscape with a ski-jumper that jumps right out of the pullover… the skis in V-shape, the jumper seen through that V, you know? (like this kind of: http://www.cogito-magazin.de/uploads/images/skispringer(1).jpg)
if you want to stay “easy” on the design and not incorporate a picture, a cool fischerman’s pullover, turtle neck, would be something they can feel like a big boy in. or a raglan with different color sleeves and the team number in the back? maybe even with the name worked in (even though that CAN be bad torture for the kid with the name, depends on the surroundings).
Edit: I just saw a funky sweater jacket in a shop in Sweden: it had a zipper run over the middle. One in the front, of course. And then one in the back from the top of the hood to the bottom hem. you could take the whole thing appart. Well that may not sound so special… but if you make 2 of those set ups, you can zip them up with each other… so making 2 left and 2 right in 4 colors / designs total would leve a kid with a lot of options. Kids like to decide… so you can give them the choice.