My niece asked me to make her highschool graduation cake for her party and we are kind of in quandry as to the design.  She would like to use her high school colors(Blue and White) but also the colors and mascot from the college she will be attending (Michigan State- Green and White)  Any suggestions?  She would like somethining tiered to serve approx 100-125. 

Maybe make the bottom tier high school colors, the middle tier college colors and the top tier something unique about her.  You can add the mascot or the maybe the initials for each school to the appropriate tier.  Kind of like a progression of her growth or go the other direction with the tiers to symbolize that she is unique not matter what the changes.