Good point about the binos; you've gotta have binos. THey show you where to point the scope. But they'll never impress a child like that big shiny telescope would. (At least not until they've learnt to look through them and not just at them.)
The 6" Dob would be great, but it is still a huge scope for a child. I didn't even realise it was an f8. Pity they don't sell
the 4.5" Dobs in Australia (to my knowledge). That would really be a perfect child's scope. It's still big enough to impress the uninitiated by its sheer size, and it's also big enough to show plenty of heavenly wonders.