I've stu,bles across the marvellous (not mine) idea of getting my son a hover board/ segway thing for birthday mid-December and getting a go-kart adaptor for it for Christmas, BUT no idea where to buy either- go-kart kits there are loads of on Amazon, but what about the actual hoverboard?? Ideas would be great. Or electric scooter might be a plan too. He'll be 7