blazer aint no unibody...your thinking jeep

 

i've stumbled across a few blazers and jeep that have wanted more room like your wanting and they made it into like a conversion van, it would raise the roof 3.25" but for the extra length you would have to cut the frame and the best place to cut it at would be right under the front seat and i would say add about 6" to 1ft. keep us updated if you decide to do