If the shocks are maxed out on full extension then yes by getting longer shocks will help but may bottom out quicker too. One trick is to move the top of the shocks more inboard to accomodate the longer shocks like this.... / \ or run a mount through the bed. If they are maxed try taking the shocks off on the rear and see if it gives you more flex, if it does then you could use a longer shock.
