[Phil]

Paul
Take a look at the roll bars available in some of the race catalogs. There are straight lengths available in 1" increments, with various diameters. Also available are some really nice arms splined for the bar, with connections for heim joints at the end. Most of the arms can be had in straight and various bent configurations to fit your chassis.
If you really want to get crazy you can get an arm with a bearing and cable attachment to vary the stiffness of the bar as you drive.
Good luck
Phil