Do like the crane guys do. Crib it up.
Jack it up, use smaller stands to hold that position. Or blocks under the tires. Get some cribbing (a big chunk of wood) and place it under the jacking area, then put the jack on it and repeat, until you have the height you need. And by cribbing, I mean something minimum like 6" x 12" x 4'.
Somewhere, I've got a picture or two of the time I had to get a boom truck 4'-5' up in the air as I had to remove all 4 A-frame outrigger cylinders. Using an air powered, 20 ton Blackhawk bottle jack and a bunch of cribbing.
If you still need a tall jack, OTC and other make a tall lifting jack, but your looking at $800-1200 for those. If you go to a bumper, frame type of lifting jack, that will put you in the $4000-5000 range. Cribbing will be much cheaper.
