Options are a bit limited for kids that age, but Altura do some kids stuff as well.
There are a number of websites that sell kit for kids (e.g. Venussports), but frankly they all just come up with the same very limited items from Altura, Polaris and some Sugoi. There are some on-line stores (through Amazon marketplace) that used to sell Jeantex waterproof jackets as well.
Not very good choice though, I'm afraid. My eldest is now 11, which at least means that I could get him XSmall 661 gloves this winter … in fact I can see 661 becoming his staple brand in the coming couple of years.
