The game limits the resolution to a few small 4:3 sizes. With this fix, most resolutions reported by the graphics driver should be usable. It requires an unencrypted (NoCD) version of the game. I've tested up to 2560x1440.
Edit SC3U.exe with a hex editor,
search for the the byte sequence:
8b 4c 24 04 8b 44 24 08 53
and overwrite the first four bytes with:
c2 08 00 90
then search for the the byte sequence:
8b 4c 24 04 8b 54 24 08 81 f9
and overwrite the first four bytes with:
c2 08 00 90
Have fun!

