If nature has taught us anything, it's that even in preferences that are innate, there can be some who hold odd preferences. For example, consider sexual preference. There are some who are heterosexual, some who are homosexual, and some who are bisexual. The people who are homosexual and bisexual go against the norm. Also, I can't think of any preference for which the two sides have a fairly large population, and it doesn't have some people preferring many parts of both sides or not preferring any side. Therefore, it seems clear to me that, in Socionics, there will be people who, for example, are equally adept at using both thinking and feeling (or who aren't good at using either).
I'm just wondering, what would the ego, super-ego, id, and super-id structure be like for such a person?