Will this cake work and taste good?

I want to make a cake for my boyfriends birthday. We have a lot of people coming to this party, and I didn't want to just make a Key Lime Pie, it's his favorite, because that's just normal, and he's not normal at all, he's unique. This is why I want to make a unique cake. I was thinking of making a sponge cake, because it's easy to cut, and then making a key lime pie filling, and then making the key lime pie filling like a layer in the cake. Does that make sense and do you think it would work and taste good? I would do like a fluffy white icing, or if you have a better suggestion, then I will do something else, I would love your help, his birthday is on the 8th, so I neeeeeedd help :D thanks soo much.