I need this as well, because I have resorted to using my Canon Kiss X5 DSLR for webcaming. I would like this feature because in particular games it is more economical to have ones facial video in particular corners in the screen, and for those of us who have our cameras at an angle off to the side of us while we perform gameplay.
Now, if we often switch between games it would not be very much ease of use if we have to change to camera angle physically every time we change streaming set ups. For ONE, it would look awkward if I appeared looking in the opposite angle of the gameplay. SECONDLY, I'm kind of amazed that other softwares don't entirely support such a function, and I know you know it would not be hard to implement such a feature.
I think this feature is actually needed more than typical users make mention of especially for the nature of most streamers are gamers, but even if the streamer was not of gaming this feature seems like it should be considered as a necessary one.
I NEED it, and I'm sure others do to, they have just been "Making due" without it.