How about lifting range? 6 ton I am sure is more than adequate from a capacity standpoint. Haven't actually measured the height needed, but w/ my floor jack raising the frame, I have to add a brick to the saddle to get the tires off the ground far enough to pull the wheel off. I figure another 6-12" to make room to move around under the truck w/o banging the coconut on something.
I was lifting the whole side of the truck to rotate tires. Both tires off the ground at once. About a 1 1/2" clearance. Not much wiggle room: wheels have to get pulled straight out and replaced same way. I'll put a ratchet strap on the shopping list next trip to Pep Boys. Thanks for the tip.
By far, the bast place to buy jack stands and jacks is Costco.
Harbor Frieght has great prices, but their quality sucks. Cheap tools are one thing, but having a jack fail while you're under the truck is no laughing matter. Get quality-made equipment when you're lifting your truck.
My experience with Costco has been stellar. Great equipment at resonable prices.
Finally went out and measured: from the ground to the bottom of my frame is 12". I've decided to get these from Northern Tools: http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200305227_200305227
They are six ton capacity which is more than enough, but the three ton ones height range is only 10.9-16.4 inches while the six ton height range is 14.9-23.5 inches. I figure with the frame 12" from the ground, 16" won't give much room to work, and that is fully extended. These stands also have a security pin to prevent accidently letting the stand down. Unfortunately, I drove all the way out to Northern and they were out of them. Next time I'll call ahead. $37/pair or $25/pair if you don't want the extra locking pin.