It’s been rumored for some time, but now it seems the rumors are true. GM is going to debut a Hummer H4 concept vehicle at the Detroit auto show this January. Obviously, details weren’t released, but our best guess on the specifics of the future Hummer is that it will be a smaller SUV than the midsize H3, to take on the Jeep Wrangler and Toyota FJ Cruiser. Since the H3 is still selling at a brisk pace it seems downsizing the Hummer brand isn’t a bad trend to follow.