I have been looking into this also. So far i have found no actual kit, but you can piece it together.
The rear is easy, blocks, springs or a shackle flip.
The front is a little harder.
A couple options:
Coil spacer, not preferable but easy. a 1 inch spacer yeilds about a 3 inch lift.
$50-60
lift coil springs from
www.aribagit.com a 2 or 3 inch spring, dont know how good they are but might work. Cost about $140 plus shipping
With these two options you need to use an upper ball joint spacer to help correct the steep angle. can be found at airbagit.com.
airbagit.com also has lift control arms, but i have not heard anything as to the quality.
Fabtech use to have a lift coil and lift control arms but they are discontinued.
Now if you wanted to get a little more lift or lift without the springs you could use a 4.5 inch lift spindle for a chevy c2500. You also need the same year brakes, ball joints and tie rod ends.