Thanks Jazz. I skimped on the extra rail in the design to keep the Steel costs down to two lengths. What I'll do is find some smaller sized box section for the central bed support, put two or three support rails in there (depending on size) and use the existing single span of 80x80x3 to create the support triangles at one end. I guess at this point I could go for triangles on the 'fixed' end or just move the central bed support rail to the same height as the top rails to create a U shape. I'll draw them up shortly and ask for comments.