>>1280083Sorry OP, but you're pretty much giving up everything that makes a bicycle good for two extra wheels and no engine.
Can't store it in a small space, can't ride it through a small space, isn't light or easy to move from place to place. You'd also run into problems with terrain that you won't with a bicycle because of its size.
If you added a motor, you'd basically have a large Go-Kart or a tiny Sand Rail, might have fun either way. As is though, you're sacrificing everything good about a bike just so your clumsy ass doesn't have to fall over without training wheels.