Know someone who kept a wedge-shaped rock in the bed, and jammed it behind (or in front of) the rear wheel when parked. Still kept it in gear when parked though.
I guess you could try it - put it in gear to park it, wedge the wheel, then take it out of gear and see if it works, but I foresee a problem: if the rock/wedge gets dislodged, then the truck will be moving if it's on any kind of incline.
Had my passenger side parking cable seize about a year ago - rather it would have snapped as it cooked my rear shoes.
'03 Ranger Supercab, Flareside, 4.0 liter V6 SOHC, auto, 4 x 4 w/FX4 Off-Road Package (Level I)