as you know monotouch is the c# face of ios native api. is there any opportunity to use monotouch in ios games? i examined unity3d and unreal development kit. there is no ephesized feature like this. is there any way to use c# in an ios game engine?
For example: i want to start a phone call in a game
In Unity iPhone you can access native features of iOS by calling them through plugins. Usually those plugin methods are written in ObjC/C/C++.
http://unity3d.com/support/documentation/Manual/Plugins.html
It might be possible to write plugins using MonoTouch, and access them from Unity after they've been compiled to native code, but I seriously doubt anyone has attempted that.