Ummm, no offense, but that would be difficult as HELL.
Look at the size of a Mac Book Pro case.
The odds of you finding components that would fit inside of that would be pretty difficult, let alone components to already exceed what the Mac Book Pro already has.
Another thing is:
Where are you going to get the case?
Don't tell me you're going to swap out the current components inside your perfectly working Mac to try and cram in some bulky components, and possibly damage two computers in one night. That could end very, very badly. >.<