Yes and no...I still have my third row seat (when needed)...sounds crazy, huh? Well, not entirely crazy. There is a method to the madness...
I removed the 60 half of the seat...not for weight-reduction but to create a hidden storage area. The bottom of the seat (the bit that you sit on...or used to sit on) is completely gone.
The back of the seat (the bit that had the headrest, arm rest and cup holders) I removed, stripped down to the metal frame, sprayed it with undercoating (to make it black...and because it had a bit of surface rust), and re-attached the carpet to the back-side of it. I then put it back in the truck using the same mounting points. When lying flat (as it always is) it is completely indistiguishable from the original configuration.
I use the storage area (which boasts about eight/nine inches of clearance...I never measured) to stow gear that I otherwise would have needed to mount in a location that was visible and/or would have cluttered up my console and glove box (walkies, jumper cables, flash lights, machetes, tool kit, tire iron, and high-jack).
The area also serves as a good mounting point for the on-board PC that I installed to replace the factory nav/radio. The PC, wiring, and peripherals all mount to the bottom side of the metal seat-back; keeping it in a semi open-air environment and off the floor to avoid any possible water damage should I wander too far into a creek that is too deep. I've also mounted my fire extinguishers on the plate too.
Couple that with the fact that in the four/five years I've owned the truck I've never had the need to transport more than three other passengers (I guess I'm just not a people person), AND that I plan on keeping this truck until one of us dies...it seemed like a solid choice to meet my needs.
Besides meeting my personal needs, another thing I like about this configuration is that when loaded with four passengers, the rear passengers are one behind the other, which leaves my cargo area as one contiguous block of space. This works out good because the only time I ever have four people in the truck is if we're going camping and this allows us to store our gear in a smart manner. Plus I think it weirds people out being in that seating configuration...which adds to the perceived 'adventure' of just being in a Hummer.
So...not crazy...just whittling it bit by bit into the truck that I need.