I don't know if this is as uncommon as you think. We too did not have any one 'real' or original person. We had a bunch of front runners that cope with different aspects of daily life. In the structural model of dissociation, this is fairly typical. And, contrary to what some posters might think, the structural model of dissociation isn't all that different to the general understandings of DID... it is simply a way of describing how and why DID develops and a way of classifying dissociative (system) structures.

In a very real sense *everyone* is the original. Not a single one was created out of nothing, or was surplus to the original born child.
Not having one main host just means that the day to day tasks were split up amongst different front runners. The greater the ability to dissociate is, the more splits there will be.
That doesn't necessarily imply that the abuse was more severe, either... according to the structural theory of dissociation, dissociation occurs when there the normal course of developmental integration is disrupted... and the extent of the dissociation may depend on the developmental stage of the child when the disruptions occur. (As an analogy, fetal alcohol syndrome is now known to occur when the pregnant mother has ANY amount of alcohol at a very specific stage in fetal development - around the 21st day, I believe. So the embryo of a mother who consumes excessive amounts of alcohol throughout her pregnancy but - by chance - doesn't happen to have a drink on that very specific day will not develop FAS, but the embryo of a mother who has ONE glass of wine during her whole pregnancy but it's on that critical 21st day may develop FAS). I use this analogy simply to illustrate the fact that it is believed when disruption to the normal course of personality development (trauma) occurs at a certain stage the effects may be much more profound than if the same trauma occurred at a different stage of development.

It would be interesting to understand if the timing of trauma in relation to typical personality development resulted in different types of dissociation, too. (I am thinking more of the clear cut full amnesia type of dissociation vs the more blended, hidden type of dissociation with less clear-cut time loss that some people experience).