Honestly, the gender bender usually seen in Fate is pretty boring since the Servants are alternative versions that have no connection to their male equivalents from the real-life myths.
The Fate/Strange Fake LN has some actual gender bender with one of the masters being Francois Prelati(male) who reincarnated himself as a cute girl into modern times and then summoned his old male self as a shota servant. Strange Fake Jack the Ripper also fulfills this fetish to some degree.