John Ratcliff was one of the original developers on PlanetSide. He is likley responsible for all the old shots of the famed purple buildings that never made it into final release. A couple of years back he put together a very interesting blog entry covering the game from it's infancy all the way up until release.

I designed the entire client side game engine myself and I had a lot of fun during the development process. One of my regrets is that, in many respects, the final game did not look nearly as visually impressive as it did at certain points during development. There were a number of reasons for this.

There's also a bunch of old screenshots on his blog that show the game in all phases of engine development. At some point there were even NPC's in the game. Imagine driving your Prowler through the countryside and running down some dinosaur looking beast?

Head on over to his blog to check out all of the screenshots and a brief description of each, it's a very interesting read into the development of the original PlanetSide.

Update: Additionally DviddLeff on the forums uncovered some of Brett Brileys work on his website. He did some work on PlanetSide as well as Core Combat.