Hey Guys,
Thought this might be of interest to you...
http://shop.ebay.co.uk/cybernezz/m.html
I started with my demon X140 - but it was too noisy
apparently when I was following my son out on the dirt bikes.
I ended up selling the Demon X140 and started new electric project! Will have a really mint "Demon X Electric Pit" in the next week or two to share with you..
Anyway. I'm selling one of the little bikes that I have (same as my sons) - got it on ebay (link above).
Its recomended for 12+ although to be honest, I'd say 4+ to about 10/12.
My lad is 5 and pictured on the auction sat on it in one of the pictures.
Fully charged it will run for about 1 & 1/2 hours. Depends on the size of your child and whether or not they pin-it constantly
I think these bikes are amazing. Charged up in about 2-3 hours, full suspension & great in the mud.
Best of all they are completely silent - so your neighbours can't complain!
Couple of pictures below.