Hello, new guy here... I've not created anything worth showing to anyone. But this topic is something that's been bothering me for quit a while and every time I mention it to one of my friends they just shrug and act like I'm making it up or something. So excuse me for jumping in without a proper introduction, it's just nice knowing I'm not alone with this problem 
For me it's a small FoV tied to the weird mouse-acceleration console ports tend to have (just a fact, I know it's needed for playing with a controller's thumb-stick*). Games that use UE3 usually let you turn it off through editing the .INI files. But when there's no such option I simply can't play the game for more than 10 mins without getting sick. The camera reacts like it's orbiting your head and the crossair is going all over the screen. Even if I didn't get sick I wouldn't be able to hit my targets like that. In other games I'll get accused of having aim-bot occasionaly, so don't say there's nothing wrong here.
Bioshock's pacing is slow enough to not have it affect me. But Dead Space and Far Cry 2 are two games I had to step away from. Which is a shame tbh. In Borderlands I'm playing a sniper and with the sensitivity turned all the way down and my DPI up high it's doable... as long as I don't walk and keep running.
Yes, I do get it in cars too. Though only when someone else is driving and they accelerate too fast/ break too suddenly. Most people I know find this annoying and would call those types inconsiderate [drivers].
So is it really that much to ask for a FoV slider in the game's options?
If you insist on calling it a medical condition please consider that according to Wikipedia "About 33% of people are susceptible to motion sickness even in mild circumstances". Thats a pretty big number.
* Which a lot of devs seem to be doing too nowadays.