Interesting design,

How do you plan on attaching it to the up-rights? Do you plan on mounting it directly to the plates for a axis?

Also Jonathan I know you have FEA software so if you have the time run realistic loads through and see what you get. Remember to add the stiffness that the Hiwin will add. I am probably missing something and hope some one point it out. Also what thickness UNP steel beam are you planning on using OP?

Michael