There aren't any Rubicon-specific springs, but if you have stiffer/taller ones, someone may be interested in them. Each spring should have a tag - look at the last two numbers to determine which ones you've got. Higher numbers mean a stiffer spring.
The fronts usually range from 14-19 and the rears are 54-60 (correct me if I'm wrong).
Rubicon shocks seem to go for ~$150.