There's a new game engine coming to market for the PC, XBox and PS2 going by the name of Myriad. This engine is being developed by LTStudios and while they don't have a demo available yet (in the works), they are providing some information as well as a couple of screenshots. Their claim to fame seems to be the ability to put alot of polys on the screen without the lag. You can check out their website of download their information package for the screenshots and additional information. There's more information below.

From the Myriad projects page:

 LTStudios Ltd has developed a toolchain and engine system - Myriad – which is specifically targeted at delivering highly populated environments.
This ability is not restricted to populations of characters, but is equally capable of handling large volumes of vehicle traffic or any other active game content - cars, animals, soldiers, attack craft etc.

Myriad performance on PlayStation2 ® and Xbox ®:

500 lit, skinned and fogged people at 60 frames-per-second using three levels of detail (LOD) as follows:
* LOD 0 (near) 1928 triangles
* LOD 1 (mid) 1046 triangles
* LOD 2 (far) 325 triangles

500 different & separate animations
500 AI decision paths – each character is managed individually by the AI system

Xbox
21 million triangles per second

PS2
16.7 million triangles a second single bone animated
14 million multi bone
32.6 million triangles per second prelit landscape system (8 tick renderer on vu1)
Stats above relate to LOD only being used on people, and currently is not used on these as aggressively as is possible

Myriad is the delivery point of a comprehensive platform-agnostic toolchain which enables rapid multiplatform development – the toolchain is designed with a focus on visibility of assets throughout the production process.