Landships? Get your head out of the clouds, all they become is slow moving cannon fodder, and the most amount of speed you could get out of it is a mile per hour, similar to the real life Shuttle Crawler operated by NASA. In combat it becomes a massive target that could easily be quelled by an enemy. Basically all you would have created is a giant redundant platform for light weaponry, which is at most what you would be able to operate without sacrificing what little speed could even be managed.
I'm sorry but it is a pointless design, and I can tell this was inspired by some video game or anime you've been entertained by.