You could do what the suspension butchers do, and remove all the spring leaves except the main leaf with the frame pivots and the shackles, and control the ride height with air bags. Turning a real truck into a Cowboy Cadillac that will never have anything heavier than a Yeti cooler in the bed sort of makes pickup-type spring rates a moot point. Don't forget to install shorter shocks to avoid bottoming them out.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!