I came up with a Iron Blimp that worked pretty good, it had Hydros (for vertical only) on the inside tanks and all so technically it was hydrogen filled :) and then I used regular atmos for for left right forward and back. and there was no option for ship being upside down as this would not have been possible. But I lost that save game so I would have to rebuild it as i did not blueprint it. but I am unsure what other steampunk would be available, maybe something with wings and helicopter blades, like an ornathopter