Yes its definitely possible to do it without removing the hinges. I chose to take the door off by removing the bolts holding the door to the hinge... which required unplugging the wiring harness, which requires unbolting the e-brake so you can get to the plug (damn, you would think another 1in of wire would put them out of business...)
Once the door was out of the way, I cut the old pins in half and popped out the pieces. Then I took the door side part of the hinge, and use a vise to push in the new bushings, reassembled the hinges, and reversed the disassembly. Putting that e-brake back in was a $#$#%.
Mine was so bad, the pin had worn through the bushing and has started wearing into the metal of the hinge.
However, I didn't think it was possible to do it with the door on (and thats why I took it off), but after seeing DeRocha's thread, I think it would be much easier to do it his way.