Are all Droids the same size and where can I get a 3D Case for a Droid 4?

I'm considering getting the Droid 4 but if i get it I would like to get one of those cute 3D cases like: &w=600&h=600&ei=J7T3T9KWHrDk6QH8m53eBg&zoom=1&iact=hc&vpx=170&vpy=127&dur=390&hovh=225&hovw=225&tx=110&ty=113&sig=103858914029692646383&page=1&tbnh=124&tbnw=124&start=0&ndsp=31&ved=1t:429, r:0, s:0, i:75 yet it seems i can't find 3D cases for the Droid 4 if I were to get a case for the Droid Razr or some other kind of Droid would it fit? Are they all the same size? Do you know where I can get a cute 3D case for the Droid 4?

Phone cases are made for specific phones - the cases for a Droid Razr will NOT fit on a Droid 4.