Too short of shocks would cause it to carry the tires off the ground, not keep it from hitting the bump stops. If you're not hitting the bump stops, you might check the torque specs on your spring mounts and shackles.
Shock can be purchased by dimensions. You already know the mount sizes, you just need the proper length. Take the distance from the end of the bump stop to the axle tube and subtrack that from the static measurement(mount to mount w/the jeep setting on a hard level surface). then subtract about 1/4" to 1/2" so the shocks don't bottom out. And you have it, the collapsed length. Extended length is unimportant, It can't be anymore than a little less the twice the collapsed length.