There are MTBs with 20" and 24" wheels for smaller riders, which probably is the closest thing to what you're describing. These wouldn't be BMX bicycles though, since BMX bikes don't have gears and have a taller handlebar than a mountain bike.
No such thing. Trials is a sub-sport of mountain biking, often called "mountain bike trials". It's a sport similar to motorcycle trials where one takes a light bike and hops around an obstacle course. You might have heard "BMX" and "trials" in the same sentence because a BMX bicycle can essentially make a good trials bike with minimal modifications.
it matters what you are going to use it for
Yes, if you can find the correct bottom bracket for the frame.
It will if you have bmx (or bmx style) cranks.
It's more a question of "different" than outright "better".If you want to use your bike to get around with, then a mountain bike with gears and bigger wheels is better. It will be faster, less fatiguing and offer greater rider comfort.But if you want to do BMX style riding, with jumps and tricks and that, then a BMX is a better choice.
you can find a BMX bike in halfords
As a general rule if two bikes are in the same price range, the smaller of the two will be lighter. This because there is less material used in the smaller BMX due to it's much simpler construction. But, when you head for the high end, a flatland or racing bike is going to be much lighter compared to a mountain bike.
The bmx thruster rampage bike is a exellent bike
One can buy a custom BMX bike in Las Vegas from a few stores. One can get a BMX custom made from 'Just BMX', 'Bolder BMX', 'Bike World' and 'Vegas Bike Store'.
No, you cannot put pegs on a mountain bike for stunts and tricks. Mountain bikes are not designed for this type of use and adding pegs could compromise the bike's performance and safety. It is recommended to use a BMX bike for stunts and tricks instead.
you could throw that thing off the roof and it wouldn't break.
No, a BMX bike's serial number does not uniquely identify it as a BMX bike. Serial numbers are used for tracking purposes and do not indicate the type of bike.