Maybe an extension of Mx, Ms, Mr: Mixtress? (I suppose the “ess” is what makes it seem feminine) Or just “Mx. Name”, like how “Mr. Bond” can feel like a single term in the James Bond movies. (Mx. pronounced “mix” feels right here)

Let’s see:

  • Mistress
  • Mister

The end should be changed in stead. You can do the X thing: Mistrex (or Mistrix to keep the “e” part pronounced as “ih”). Or change it another way: Mistro, Mistrez?

Ooh, this is a cool way to come at the problem. I am surprised I didn’t think of this, as I do rather like the title “Mx” (even though I don’t use it myself — I use Ms.)

I like Mistrex/Mistrix, that seems… sensible to me.

You could also do Miztrex/Miztrix, if you want to make it a bit more distinct.