you can do pretty much most stuff with a 30lb hardatil, my bike is more than capable of most things and with some lighter tires could be under 30lbs. Sitting about 32lbs with 2.5 tires just now.
Yea, I agree you can do whatever you want on a 30lb hardtail. My point was more that to get a big-forked hardtail to that kind of weight you will need to use parts which aren't tough enough to take the kind of abuse you would want to dish out on a 160mm bike.
For example, your bike could be sub 30 with light tyres – which would pinch flat whenever you tried to send it. So why not just use say a 130mm fork on that sort of bike?
Ultimately I'm just discussing it for the sake of it – obviously people can ride whatever they want, its all bikes!