I have a bunch I found that I think are cool, but here's my main pick
An interesting bit behind what I was looking for here: I always thought the interface for the Sega game "Soldier of Fortune" looked pretty cool (the game's got a mystic vibe about it mixed with mercenaries and military dudes, including a scientist with questionable character; not that that's a bad thing), so I went to find something that had a more military style, and there were a bunch that looked good (and they did have the Soldier of Fortune skin as well). I picked the one that I wanted that closest matched Ross's criteria from the GUI video. This is a darker theme (that part is kind of my preference) - but not too dark in case you go to look at a bright picture or something, since it has those lustery spots and plenty of room to add lighter shades. I have a runner-up theme that might match that criteria better, but I didn't know how dark Ross would allow, however I still picked this one for the contest because it matches Ross's computer theme where he's got his surface and core drives, and this sparked my imagination of taking a submarine to the bottom of the ocean to take a gate into the core of the planet. Or even a similar machine to withstand pressure drilling into the surface of the planet.
Here's my second runner-up, and I think it could also be a winner, but I thought the immersive aspect of the first one might be more to Ross's preference.
The_Legend_Of_Winamp.wsz This one makes me think of operating a set of military intelligence equipment in a tent. It also might be just right for that light/dark balance we all crave. This also happens to match the theme of Iron Harvest a bit more.
Cool video game looking theme (maybe a little too busy)
Actual video game looking theme
Cool old school video game swamp looking theme (like the swamp from Soldier of Fortune)
This one reminds me of Magic the Gathering (even though I never really played that game)
Something I'd try for a day to see how I like it
Mood setting theme
A different light/dark balancing theme
The actual Solder of Fortune theme I started with (not picked because of the man standing there)
I LOVE IRON HARVEST!! SAXONY FTW!
Favorite line from the game: "What does the empire require?" Gives me goosebumps knowing the Third Reich is coming.