If your sticking point is the floor rack work from the knee level may help thinken your whole backside, but will likely do little to help your dead, off blocks, or lightened band work are better alternatives IMO.
Blackbeard, my power-rack sound like your, the bottom holes are still not much past knee level. I have blocks though that I use in conjunction with the rack so I can pull from anywhere from about 2 inches above where the bar would be on the floor, to a 4 inch partial.
For BB'ing purposes, rack pulls at knee level are an awesome way to thicken your whole backside.
Iron Addict