So… Unfortunately in Brazil, we don’t have radioshack stores, so we can’t buy the camera enclosure for the camera assembly. If anyone could help us, we don’t need the piece, we need only the measures to make one by ourselves. 
The suggested project box is 4x2x1. However, if you are building your own, you don’t really have any reason to use that size, as long as what you make fits.
A great place to look up in Brazil is the Farnell Web Site, I bought some boxes there last year for an electronic project.
I would just build your own and not use the radio shack dimensions. With the radio shack one you have to cut all sorts of holes and such in it for cables, whereas if you make your own you could make it slightly deeper and have your cables come out one side.