Jon:
New 650GSs have a braided front hose anyway (those built/bought in the last year). So, why not buy the genuine BMW part? I'm going to do the same for Lisa's bike at her 6000 mile service this spring when I change the brake fluid.
From my experience of riding the 650, I don't think the rear needs a braided house. Rear wheel braking on the 650 is much stronger than on the 1150. It really needs a braided hose on the front, but personally I wouldn't bother with the rear.
Simon