That is great! Please post your design when you get it done. I made one before out of a styrofoam cooler, and a light bulb, and it didn't work. Then I bought a Little Giant incubator that works great.Now i am going to make a homemade incubator that uses up electricity!
One important thing in using an electric incubator is your room temperature needs to stay the same all the time. It really effects the inside temperature of the incubator, which effects how the embryos develop.