I bought a pair of 6 ton jackstands at Wallyworld for $24.95. Sure, they're taller and it may be a bit more trouble getting the Ody lifted up that high, but since it's my (somewhat portly) hide that I'm trying to keep in one piece while I'm working on the Ody, I figure it's well worth the money. I plan on getting another pair next payday to make rotating the tires a breeze.
Look at it like this (if you will). It's a relatively cheap investment that will (literally) last a lifetime. I'm sure there are good reasons (and we're probably about to hear all of them after I post this) why smaller sets of jackstands are better. I have to be honest and tell you that the piece of mind that I get from having those two monsters parked under the van when I'm working on it is priceless.