Unfortunately, it doesn't look like Doc Fate made an actual appearence in Vertigo's Madame Xanadu series written by Matt Wayner and beautifully illustrated by Amy Reeder Hadley. It's a shame too since many of DC's mystical characters had at least a small cameo. However, the Phantom Stranger does mention him, somewhat subtly, in the following panels:
*Oh yeah, we are less than a week and a half away from Dr. Fate's return to Earth 2!