Still would love to see a real widescreen solution with added pixel left and right.
This has been requested before... I'm pretty sure that it's basically impossible to do, given the way that Outcast was coded. Personally, I'm amazed that the high res patch even works at all, given that the original game couldn't go higher than 512x384. Back then widescreen monitors didn't exist, so most developers didn't even consider supporting resolutions with different aspect ratios.
So yeah, I think that the patch enables running in widescreen but this will cut off the top and bottom of the image, and there's no real way around that.