Does your truck have the factory sway bar brackets riveted to the frame? How much is your truck lowered? I was in the same situation as you and installed this:
http://www.summitracing.com/parts/bel-5404
My Jimmy didn't have a factory sway bar so I drilled the frame and bolted the brackets supplied with what I listed above right to the frame. Worked great and I'm very pleased with how it handles. You can just barely see it in this pic.