This should help.
The e-brake cables to make the e-brake work when using the NBS rear discs came from a 2001 RCSB 1500 truck. basically, unhook the OBS rear cables at the connector and then connect the intermediate cable to the OBS front cable. then route the two rear cables from the NBS, make a bracket for the cable sleeves, and connect it all. not too bad, took me about an hour and change, taking my time with it. the brake swap was more involved.
Grab all the rear brake parts, and the e-brake cables. if you want dual piston calipers, look for a tahoe, yukon, or suburban, as those had the dual pistons. one thing to note - you need to get the clipers and caliper brackets from the same truck. reason - they changed the rear brakes in 06 as well as the fronts, and they went to a beefier rotor and different pad design. those parts will work with the e-brake setup from an earlier truck, they bolt right on - but the caliper brackets are different. Also, the e-brake cables on the SUVs have different cable ends than the truck do, so if you get backing plates/e-brake assemblies from a 'burb or a 'hoe, get the brake cables from it as well. the intermediate cable from the vchevy truck I mentioned is universal, so you can just get it from the parts store.
so get the calipers, caliper brackets, backing plate/e-brake assembly, hoses, and rear e-brake cables from the truck, and then go find an intermediate cable from a 2001 chevy RCSB truck. bolt it all together, and BOOM. rear discs. throw in the NBS master cylinder, and you have good pedal feel.
