This is true. GM is completely redesigning the body. They have some early test mockups of what they are calling the "Delta" platform. They are using new, lighter weight materials, new cell technology to increase bulk while drastically reducing mass and embedding special color markers to even reduce weight caused by painting processes.
I have obtained a photo of an early design concept, although I can't reveal who passed this too me. I'm sure GM will probably force the moderators to remove this so please view this one fast.
See below.
Yeah, I'm with the rest of you guys. I think GM may try to reduce weight, but I think that 1000 lb figure may have been misheard or something.