I remember reading an article online, back when the first rumor of Apple acquiring a deal with the liquid metal company, about how the material itself is worth almost 5 times the price of aluminum. I'm not sure if Apple is trying to cut profit margins, or doing their magic, or even cutting costs by buying in huge bulk quantities(sounds very reasonable to me considering their past transaction history) but it seems really unlikely that the whole mbp case will be made out of it. Though, I have also read that you can make a weaker version of that alloy, that still is stronger and lighter than aluminum, can be only a bit more than than the price of aluminum, and is a lot easier modify its color.
Honestly, I wouldn't care how heavy it would make it, but I would love to se a stainless steel MacBook Pro
I mean, realistically, you don't have to look far to see how expensive things are that possess this liquid metal allow. The Vertu phone isn't really anything that special in terms of what it can do, but it has a liquid metal casing, and a sapphire screen, but costs thousands of dollars. The Omega brand of watches makes a big deal about the liquid metal they used, even though it's only used in the numbers and surrounding area, which makes its true purpose of that alloy absolutely useless.