Academic definitions aside, there hybrids have to choose a very serious compromise due to the balance:
if you make the base light (surface pro case), you won't really have a laptop, instead a tablet which sits on your legs.
if you make the base heavy, you're making a relatively heavy laptop.
now, there is of course a spectrum of choice, but practically speaking, even they make a very light tablet part (say, 850 grams), with a "heavy base", you will add 550 grams at least (550 being an odd balance).
I'm absolutely happy to have a 1.4 kg hybrid, but it's not going to compete with the upcoming wave of ultrabooks (note that I'm somewhat skeptical it will be 1.4kg, I bet it will be a little more).
Update: they've just published the spec, and it weighs, as I was suspecting, 1.5kg, which is not bad for a sturdy (I assume it's going to be robustly built) hybrid.
Academic definitions aside, there hybrids have to choose a very serious compromise due to the balance:
if you make the base light (surface pro case), you won't really have a laptop, instead a tablet which sits on your legs.
if you make the base heavy, you're making a relatively heavy laptop.
now, there is of course a spectrum of choice, but practically speaking, even they make a very light tablet part (say, 850 grams), with a "heavy base", you will add 550 grams at least (550 being an odd balance).
I'm absolutely happy to have a 1.4 kg hybrid, but it's not going to compete with the upcoming wave of ultrabooks (note that I'm somewhat skeptical it will be 1.4kg, I bet it will be a little more).