Is there a single member of the Einzbern family who is a human being? From the information I could find, nearly all known members of the Einzbern family are (female) homunculi (Justeaze, Irisviel, Illyasviel and all the maids), the only exception being Jubstacheit, who is supposed to be an A.I. controlling an array of humanoid golem bodies.

Is there any information on Einzberns who are actually human beings? Are there any alive at all at the time of the events of Fate/Zero and Fate/Stay Night? If there is not, can the Einzberns actually be considered a "bloodline" in the strict sense of the word, or are they more like an army of self-cloning homunculi?
The Einzberns from the beginning were a factory of homunculi. Per the booklet released alongside the DVD for the Unlimited Blade Works anime:


  • The origins of Einzbern
  
  A factory originally created by the students of the magician who
  realized the third magic. Began in the year 1 AD.  They attempted to
  reproduce their master’s miracle, but couldn’t do it themselves, so as
  an alternate plan they tried to recreate a specimen identical to their
  master and have it reproduce the magic.
  
  After nearly 900 years of effort, Justeaze—the homunculus who would
  come to be called the Winter Saint—was forged.  She was a model that
  strayed from what the magi had intended, created completely by
  accident, but her abilities were equal to or above those of their
  master.  The magi should have been elated about Justeaze, but they
  couldn’t be happy. After all, she was a mutation that was born
  regardless of their own techniques or skills.  Even if that specimen
  was to reproduce the third magic, that conclusion would be harder for
  them to bear than 900 years of failure.
  
  The magi deperately attempted to create a homunculus that excelled
  Justeaze by their own techniques.  The artificial intelligence created
  to act as the castle’s central management—the golem Jubstacheit—was
  the pinnacle of their craft, and became the father of all homunculi
  created at Einzbern.
  
  Justeaze succeeded at proving the third magic.  However, it was not
  cost-effective. Justeaze’s use of the third magic was like careful
  knitting. It would take several years to save just one person, making
  the salvation of the entire human race virtually unattainable.  In
  addition, while Justeaze herself did not age, her body was so frail it
  would take little to kill her, so she could not leave the castle. 
  Since her intelligence and mentality were also unaging, she did not
  develop at all. From an outside perspective, it was as if she was
  repeating a single day for all eternity.  If she were to leave the
  castle she would be freed from this “single day,” but the act of
  leaving the castle signified an easy death for Justeaze.
  
  In the end, they accepted that humans could create something that
  surpassed humans, but not something that could save humans. … Or
  perhaps they would not have failed if a miracle like Justeaze had not
  occurred.
  
  The magi despaired the limits of their abilities. Some abandoned the
  castle, while others took their own lives.  The homunculi left at
  Einzbern were abandoned by their creators, but in their purity, they
  continued to operate the factory for the sake of the creators’
  ideology—the salvation of humankind, the reproduction of a miracle.
  
  From then on, all homunculi created at Einzbern were based off of
  Justeaze.  Jubstacheit created a humanoid terminal unit, and used it
  as the manager of Einzbern. Though by the end he operated even Acht
  (the eighth humanoid terminal), he did not possess a personality.  He
  only included the necessary “humanity” to operate the castle and
  reproduce the third magic into each of his humanoid terminals, and
  made them act like humans.  Jubstacheit is essentially an automaton
  that cannot progress, but continues operating in perpetuity. His way
  of existence is just like an old clock ticking away, being forgotten
  by people before running down.