Aether was cannibalized into Liar, really? I knew it was cannibalized into something but I didn't think it was Liar...
You can (probably) get Dragonsteel from the BYU library, or Inter-Library Loan it from them. It's always in high demand, however.
I am certain you won't be able to get Liar of Partinel, however, in any way, except for the sample chapters that are on Brandon's site, if you look closely. Apparently a draft was finished, but Brandon was attempting discovery writing and it didn't work at all. He said on Writing Excuses it was a bad, uneven draft that he had to pull from his writing group. He had to drop it for the Wheel of Time, so he never got to revise it. So, Josh and Mi'chelle asked for Liar, and Brandon denied them. That's probably for the better; if Brandon said it was really bad, best to trust him.
There's a reason why these books aren't published, guys. Amazing, they are not. Not saying which of them that I've read, but seriously...
I do try not to tease. It's not fun for any of the members, and I'd get frustrated if I were you, too.
There aren't many revelations, though, trust me. There isn't a massive twist that will change everything. And if it makes you feel better, I haven't read Aether either.