I also did a full beam instead of I-beams. I figured these columns should be more like the support columns at the base of a building - hollow core and thick walls. But I also imagine that a lot is going to rest in the nature of the materials used. These are going to be alloys that like a samurai blade allow for a mix of rigidity and flexibility.
It turns out that I-beams, regardless of material used, will always be stronger than "solid" beams. I have to get back to work so I don't have time to discuss all the reasons why, but to sum it up, the mass of a solid structure works against its loadbearing ability especially when we're talking about torque. For example, a solid rod bends much more easily than a hollow tube made of the same material. It's more than simply a mass savings to use I-beams; they are structurally superior due to the way the shape physically works, no matter what sort of material the form is made of.
Otherwise, great project, I really like how things are shaping up!