If there is a tripod, there is also a bag for it one way or another. Manfrotto sells both unpadded and padded bags for all of their tripods from small to the largest with the head attached. Personally I prefer the padded bags for the added safety of my expensive tripods.
Tripod bags are a big advantage when travelling as it means they can go into the cargo hold of a plane bus or train and you know when you get to the destination that your gear will have been well protected.
Cheaper tripods from the likes of Inca and others usually come with a bag albeit unpadded.