Hey Bittergregs. I do believe my own system has consciously created alters. Many times, in fact! Nearly all of the younger, hurt child parts created internal helpers for themselves. Not alters in the sense that they come out and interact with the world, but alters in the sense that they have very distinct emotional states, a particular job, and are consistent within the system. The way I look at it is: I needed them, I had the means to bring them into being, and so I did. Kudos to me, I reckon.
Hmm, thinking about it more I can think of a couple of other alters that may have been consciously created to fulfil certain external roles that were unacceptable to the primary social self but weren't yet covered in any of the other alters job descriptions! having said that... the conscious creating of them wasn't exactly like "Hmm, I think I'll make a 25 year old alter with long blond hair who can x,y,z." VERY different to that... but somehow a conscious process, all the same.

I don't know why anyone would have an issue with deliberate creation of alters in an already established DID system. According to the theory of structural dissociation the initial dissociation is a result of a failure to integrate certain aspects of experiences. If it isn't rectified (integrated) early, dissociation becomes the primary coping mechanism for stress. Any significant stress in life after that is likely to result in further dissociation. In some systems this can indeed be a conscious process in some instances (going by my own experience anyway).

That may not be every DID system's experience, but I think it is narrow minded to believe that if something falls outside the realm of your own personal experience then it must not be possible (or it must be 'faked'). That's exactly the kind of mentality which makes DID so marginalised in the psych community in the first place.