When testing our game on iOS4 the orientation went from landscape to portrait no matter how we hold the phone (and unity is configured to Landscape Left). Has anyone else seen this problem and maybe has a solution?
Okay, let's try with a bounty. But I'm not looking for 'record movie in landscape' or do it in Objective-C as answer, those two options I've already considered and are would prefer to not solve it this way.
Assuming you're using Unity iPhone Advanced, you could easily write your own movie playback method. Just make sure to call UnityPause() before you start playing back your movie.
Here's a blog post that goes into detail about the changes in the movie player controller between 3.2 and 4.0
It seems to be a bug in Unity iPhone.
If it weren't for the fact you want to release the game in a few weeks, I'd suggest waiting until Unity 3.0 which most likely fixes the iOS4 issues.
Since you probably can't hold off that long, your best bet may be to try get in touch with Unity Tech and see if they can supply a version with a fixed orientation mode, mentioning that there are time constraints.
If that doesn't work, well, you could always record the movie in landscape ;) (Sorry, couldn't resist)
Yep I have this problem too. Don't know how to fix it, but I sure would like to :)