You could do the toque (hat) and have other items with it, such as a whisk or other tools, and maybe some food items (maybe some cupcakes or muffins).
I like the idea of kitchen tools - whisk, tongs, spatula, knife etc. surrounding the toque. As for food items, if the chef isn't a pastry chef, I wouldn't do muffins and cupcakes (funny how we have a one-track mind around here ). Eggs are important in classical training.
Other stuff you could add - neckerchief, half-apron, bandaids (hahaha)
I had found this on here recenlty but I do not remember who it was but it was an awesome cake. I am going to make it for my bro whom is a chef as well.
Do either 6 inch or 8 inch round cake and do a bundt cake and stack the two rounds and then the bundt cake upside down and then put fondant over it and you have a chef hat. I thought it was perfect.
Again I dont know who did it but if I find her, she deserves the credit.