I made mine from 3/8" tubing, 6mm steel plate, 12x1,25 threaded rod and fork ends that are used on pneumatic cylinders.
The setup looks good and strong, I used the CSP brace as a model:
http://www.csp-shop.de/technik/pdf/eng/17704.pdf
Here is an earlier post of bracing:
http://www.germanlook.com/Forums/sho...?threadid=1466
Justin