mid-digital hair? i have none
or do you mean middle finger/toe
also attraction is a highly complicated process that we in no way fully understand, and person to person depends more on certain factors than on others, so if you want to describe me as symmetricalfaceandplayfulandwithmaleattractionetcetcmalesexual, then go ahead, but it doesn't seem to be quite a useful description considering that a very tiny minority are going to be that way, so to answer your question: yes, there could be semidemisexuals, but is it a useful category of description? no, and it doesn't even assess what gender the person tends towards (if there even is a tendency for that type of attraction)