For an arctic level, a Goldeneye (64) arctic type base level would be cool. I think the main reason people don't make arctic levels is because they're just like desert levels, only they have less villages and no sand and alot of snow, so they tend to be white and bland and sterile.
As for maps and stuff, I was thinking that maybe adding a tag to the map to designate what kind of map it was, but no.
Then I came up with this. Just like a map list, you have a skins list. The skins are cycled simoultaneously with the maps, so that the particular skin for your team changes with the particular map, and if you don't have that skin, it autodownloads it to disk cache for you. Then on the loadout screen, your new team skin is displayed, or your array of selectable skins if its not a team game.
The mod could be made, so that just like in the weapons replacement, it knows your current configuration for maps for DM, AS, DOM, etc. This way, no matter what game type you select to run, you can go to the mod menu, and it can say something such as
Assault Map List
For Map "Desert Raid" skin defenders "TanCombats" skin attackers "DesertCamo"
Or say for a non-team game like LMS or vanilla DM, it could say
For Map "Urban Strike", skins
"SWAT"
"UrbanCamo"
"SpecOps"
etc.
Something that fits the theme of the map, and makes sense. And makes sense based on attackers and defenders, not on which teams which. Like for Assault, the defenders would always have flat tan combats, while the attackers would always have U.S. military reg. desert camo, or something like that.
Again, I'm talking out of my ass here, but its an idea.