If you can somehow attach the ramps to the pickup's tailgate with some sort of hinge assembly and then join the two ramps together with a cross bar just high enough to fit a floor jack under, you could drive up the ramps, jack it up as high as the jack will go, place jack stands underneath the ramps, lower floor jack, place big honkin block of wood on floor jack and repeat. As long as the ramps are secured to the bed or tailgate securely and the cross bar is bolted to the ramps securely, it should be pretty secure, even though I would use a boat winch to pull the car in and out while I steered from NEXT to the car.
Tom