those of you working on diy supports might want to look at HDPE and phenolic plastic. HDPE is what many of those white cutting boards are made of. It has the same workability as wood but is more dimensionally stable and will not split easily. Phenolic is basically layers of fabric laminated with resin. It also machines well and is stiffer then HDPE but is a bit more expensive. both of these materials are more easily worked with home shop tools then aluminum. You will still have to find metal rods though.