Yeah im pretty upset by this lack of 16:10 support, especially considering they managed to add support for the far less common 21:9 aspect ratio. I wrote tech support a letter yesterday morning why on earth this wasnt fixed in any of the updates, but ive heard nothing back.
I have a sneeking suspicion they developed FC4 in in such a way that only the "wide" aspect ratios can be displayed. I fully expect them to never get around to fixing this issue....
Play in 2560x1600 because Ubi still haven't fixed that yet! That resolution still gives you a top portion with full screen and no bars and a lower portion that's forced 16:9 with a black bar. Half of both worlds.
FC4 could clearly be easily tweaked to make it proper 16:10, they just cannot be bothered.