Hi Emerald...

This is a bold, interesting and difficult challenge trying to define a single definition for both transsexualism and Gender Identity Disorder. Difficult in such that everyone will have their own views as to where they fit within the spectrum and how far they go towards resolving that.
It is something that the Medical profession have difficulty in defining. I think we all agree it is NOT a mental disorder and should not be classified as such. Most medical conditions are either cured, go into remission, or become fatal (or someone lives with that condition for years?), so how do we define (if it is a medical condition) that someone has been cured, what are the criteria? or indeed the diagnosis?
Like Steph, I have seen many different numbers for the frequency rates of transsexualism, which are a lot higher than the ones quoted. This does not mean they are wrong, but reflect the data obtained in the study. How many undiagnosed cases end up in suicide for instance?
I think we can say that transsexuals are born, rather than becoming transsexual out of choice over a period of time and it is inherent within the gentic make up of that person. I agree with what Steph wrote in one of her earlier posts in that "true classic transsexuals" as defined in your post will undoubtedly transition, to seek relief from the condition..... but many people do (because of circumstances remain in there current Gender).
Agreement on a single, defined statement may not be possible, but we can certainly define the "statements" that go into making up the the many versions, which people identify with.
Rebecca