I used Wings3d for most of the modeling and Lightwave for the rest. Lighetwave for unwrapping UV's and Photoshop for painting the texture. I used lightwave for the composition render with a stock photo background.
Why does 'Robot Jox' come to mind? They don't make many mech movies, and the ones they did were never really that great, but I think with today's artists like yourself and the advancement of technology and special effects, they could possibly pull it off.
Robot Jox is one of my all time favs! I have it on DVD actually. There was also Robot Wars, Crash & Burn and Arena. All done by the same director.. BTW, I would love to make a mech movie. Oh how that would be the one thing I want to do before I die.