Currently the only way to achieve 6 inches of lift is by swapping for solid front axles. Components on the Trailblazer are shared by the GMC Envoy, Isuzu Ascender, Buick Rainier, and Saab 9-7x. Everything else related is still different enough to not really be swappable, i.e. the front differential on the H3, Colorado, and Canyon.
So, to answer your question, no there isn't anything out there that will magically make our vehicles capable of 6+ inches of lift. If there were, rest assured we would have jumped on it like starving hyenas on a hippopotamus corpse.