Combat related environments using real time/Vizard

[SethN12]

I am a psychologist at the Atlanta VAMC who recently acquired a BIOPAC VR system that runs VR through Vizard. I have been asked to demonstrate this system for several of the personnel here at the VA and I thought I could potentially have them navigate through a ready-made environment using the joystick and HMD. I have been browsing on TurboSquid (it is quite intimidating!). I'm looking for a combat-related environment that is compatible with the BIOPAC VR system/Vizard that I have here. I'm looking for worlds that are close to 100K polygons with textures already baked.
Any help would be greatly appreciated.

Seth