I'd make a little dome cake for the bottom part of cap, and for the mortar baord I'd use a bit of stiff cardboard covered with MMF or the like, so it's not so heavy. Put a covered button on top and hang tassle - should work for you!
Best of luck! 
Here's one easy way: http://www.ktka.com/videos/2008/may/13/19666/
Oh, wait... that was you?! Good for you for being on TV!
Thanks so much for sharing. I like the size of that graduation hat. I've made the one with the (full size) half ball and that one is too big for some cakes. I want to try yours. 
ness_p: if you look in my gallery I just did one.. it is blue with a white tassel. Here is how I did it... this is if you want an edible mini one to put on a sheet cake or tiered cake (as I did)
I took a standard sized square napkin and placed it over rolled out satin ice (or any fondant) and cut its shape with a sharp knife. Placed it on wax paper to dry (I put tons of powdered sugar on the surface of my cutting area so it would slide off to the wax paper.) I baked 2 layers in my wilton mini fill pans. I iced them with bc and let them sit until crusted then smoothed them with the Melvira method. My mortar board (square described above) dried for 4 days until it was stiff. I then placed it on top of the mini round cake with bit of buttercream beneath it. For the dot on the mortar board, I used a ball of smooshed satin ice. For the tassel I used Chocopan (a softer chocolate based fondant) and put it through a garlic press. You will have to keep adding chocopan or comparable product in small portions to your garlic press to get the length you want to achieve. I never took any of the tassel out of the press until I was at the length I needed... I then airbrushed the royal blue of the school colors and affixed the chocopan tassel to the hat. I hope this helps you out or is something some others can use! Good luck, it is easy!
Awesome! thank you so much for your responses. and thank you sugarbakerz and cakebaker.... Your tips and ideas help me out alot!Quote by @%username% on %date%
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