I looked and looked but couldn't find minnie heads but I did find mickey ones. what you can do is
buy 3/8" red ribbon with white dots
make a bow
make the mickey heads
after they harden remove from plastic
use the "chocolate" you used to make the lollis place alittle on the top of mickeys head (sort of use it like a glue)
place the bow you made on it
and there you go you got minnie heads
here's a close up of the mold I found
http://www.sugarcraft.com/catalog/candymolds/233.jpg
here's where i found it
its about the 4th pink line down
http://www.sugarcraft.com/catalog/novelties/disney/disney.htm#cand
I make tons of lollipops each year and think this would look great.
I have done something like this but instead of putting the bow on the head I make it a tie for a pumpkin. I gave it to zach PK3 class and none of them ate the ribbon. LOL