These are some Campaign Screen Models I've been working on lately.
They can only be reasonably used as models for Campaign Screens.

- Open Campaign Editor and import "CampaignScreen_*.mdx" with Import manager.
- To actually use model, go to "Loading Screen" section and set "Backgorund" to
     "Imported File", where you can choose previously imported file.

* Some files should use different "Costum Fog Settings";

1. "war3campImported\CampaignScreen_Undead.mdx"
     Fog effects; 1800, 5300, 2 { 90, 60, 20 }

2. "war3campImported\CampaignScreen_Sylvanas.mdx"
     Fog effects; 2000, 8000, 1 { 80, 60, 80 }

3. "war3campImported\CampaignScreen_Kyle.mdx"
     Fog effects; 2000, 8000, 0'5 { 0, 50, 100 }

4. "war3campImported\CampaignScreen_Illidan.mdx"
     Fog effects; 700, 1400, 1 { 40, 70, 40 }

... where first three values are "Z Start", "Z End" and "Density", inside brackets
     are Color settings.

I know these models are quite specific and probably won't serve well for your purposes,
but perhaps you can modify them and make them more suitable for you.
For example, if you hate the preset TeamColoring (doesn't work correctly when displaying),
you can change the color of Undead Arthas in "CampaignScreen_Undead.mdx" (converted to MDL) 
from "ReplaceableTextures\TeamColor\TeamColor01.blp" to
"ReplaceableTextures\TeamColor\TeamColor02.blp", making it Teal instead of Blue...
You can also change the background Skys or terrain quite easily by replacing their Skins
with your own...