Looking for a full face helmet for the kids to wear when they come out in the car with me. To fit ages 8-10 years.

Your best bet might be looking at motorsport outlets and looking for childrens karting helmets. Kids can start karting as young as 8 so there must be helmets to fit! You might find that XS bike helmets would fit, suppose you just need to measure the head size and see!

got my son one of these

http://cgi.ebay.co.uk/ARASHI-BLADE-JUNIOR-KIDS-MOTORCYCLE-HELMET-PINK-S_W0QQitemZ380205564890QQcmdZViewItemQQptZUK_Motorcycle_Helmets?hash=item5886048 3da

Lots on the 'bay. Measure their head - you might be surprised and they'll fit in a Xsmall adult one. My daughter is 4 and wears a 54-56 cm lid! One more size up and she can wear mine!