Warhammer 40,000: Dawn of War - Soulstorm

The game supports all the resolutions you can set in Windows - so it's up to your PC config.
You can set your desired resolution in game options, or from GraphicsConfig.exe launcher.

Since the game was designed for 4:3, the image at 5:4 -> 1280x1024 is distorted (look at the screenshot).
Only the menu which is rendered on the game's engine is Hor+
The game is Vert-, The HUD is stretched, movies are stretched, ingame cut-scenes behave as pillarboxed (look at the screenshots).
Visually they are windowboxed, because the game was designed to be 4:3, the scenes in this AR have black bars on top and bottom. The cut scene itself is in 1.7:1 aspect ratio, (between 16:10 and 16:9).

Using the camera mod from here http://forums.relicnews.com/showthread.php?189305-Download-camera-zoom-…
one can zoom out to counter the zoomed in effect due to vert-.