Thanks to Robert Hood, I now know about War of the Worlds: Goliath, an animated direct-to-DVD movie that gives HG Wells' Martians another shot at Earth. Only this time the humans have giant, steam-powered robots to help with the fighting. It got its start as an idea for a Heavy Metal series, so don't expect it to be kid-friendly. In fact, director Joe Pearson's expecting an R-rating.
You can see more concept art - including the Martians' tripods - here.