[quote=TentacleLord]
The lightweight can be explained by the fact that it's set in the far future, tech's gonna be improved and lightweight enough to support such things while not loosing out on integrity. [b]The height is because you'll have arm-sized stubby legs either directly underneath or splayed out to the sides, making it improbable to support it's own weight anyway.[/b]
[/quote]

...if it's made out of lightweight material, why is weight an issue?

The bolded point sort of contradicts your paragraph's first statement/argument.