The Humvee has about 5000. It's because of the bars on the top and front. Yes, Packer, I read you're topic on unreasonably high poly count. I have just recently been trying to reduce that with all my models. I could make the bars squares instead of cylinders. That would probably take it down 500-700. Remove/Change the exhaust pipe (whatever it's called) on the hood take it down another 100-200. My guess Is I could probably take it down 2000 with it still looking good.
But anyway, I'm working on a large pirate ship (not full scale) which might give me some problems with poly count. The hull itself is already in the thousands. As for making things that they request, I would be willing to try to model a harrier jump-jet. I'm just not sure if heed would script it.
Edit: I brought the hull down from 4000 polys to 1070 polys