Corinne, it is totally going to depend on your knowledge, skills, and abilities, as well as your willingness to compromise and your determination to persevere. This is a great site for seeing what others have accomplished on both the hardware side (building) and the software side of Hackintosh. I have gone the other way a few times putting Apple laptop parts into other cases, but never other parts into an Apple laptop case....
MacBookPro in a half-height floppy drive. Optical drive (slot load) is where the floppy used to go in.
Old white Macbook in an older HP thin client: Wifi and BlueTooth enabled.
And some other projects:
Mini-ITX in Hackintosh Cube (Rubik style)
Mini-STX in Apple ][ floppy drive case with slot load optical
Mini-ITX in Macintosh Classic II (hdmi input and output)
Mini-ITX water cooled 18-core in custom build case "Mac Pro Junior".