My preference is for original stories, but there are three mech franchises I'd like to adapt to live action: Eureka Seven, The Big O, and Megas XLR. These would all be standalone one-offs concentrating on each series' main themes. Giant robots are the loose connective tissue.
Eureka Seven follows a young protagonists in the time honored tradition of being traumatized by war but the world is colorful, mech ride giant surfboards through the sky, and it has an amazing electronica soundtrack.
The Big O is like if David Lynch got his hands on Batman: The Animated Series. Amazing art deco aesthetic and architecture. Set in a city that's lost its memories. Baffling ambiguous ending. Nuff said.
Megas XLR is an american cartoon that spoofs the genre. A mecahnic in New Jersey, who lives in his mom's basement playing video games, finds a mech from the future in a junkyard and has to defend the city from kaiju and aliens. The city is completely destroyed most episodes. I can not stress enough; this series is Hilarious. And the characters are written well. The conclusion of the series is rather emotional for a comedy.
