In 1995, Irvin Kershner tried to make a remake of the classic Forbidden Planet. The project never materialized, but Kershner had already marshaled the artistic talent of Ralph McQuarrie, John Eaves, Mark McCreery, Syd Mead, and Stan Winson. And the early concept work of McQuarrie and Mead is readily accessible today.

McQuarrie concept art was made available on Ain't It Cool to help get support for the now fully-funded Kickstarter The Art of Ralph McQuarrie: ARCHIVES, a book of McQuarrie's non-Star Wars art. Here is more of his work (the top image is his as well):

Film Sketchr then unearthed some of Syd Mead's work. While McQuarries are of massive sets (seriously, the people are dwarfed in every single one of those above), Mead gives a better look at the technology envisioned for the remake.

[Film Sketchr]