I have a request for a tiered cake with minnie mouse ears on top. What should I make them out of? I don't have much experience with gumpaste, but fondant seems like it would become limp and sag once it got to room temp? And should I attach them with toothpics?

For my Minnie Mouse cake I used gumpaste ears (but you could use fondant mixed with tylose or CMC) and then attached sucker sticks to the back with royal icing. It worked perfectly.

http://www.cakecentral.com/cake-photo_1417494.html

I made mine out of RCT and covered with fondant. the "head" was cake. I stuck two dowels thru making an X thru the head and into the cake. also "glued" them to the head using some RI

50/50 paste. 50% flower paste 50% fondant. leave ears to harden, make an indent in the head insert the ears and seal with royal icing leave to dry.