I remixed the original model to make this slim case.  It removes the fan, extends the vents on the top case, reduces the height by 5.75mm, uses 76.17g of filament, and takes 5 hours to print.

BOM:

• Bottom Case - M2.5x10 (or 2-56) screws X2
• Top Case - M2.5x6-8 (or 2-56) screws X3
• Access Cover - M2.5x10 (or 2-56) screws X2
• Front - M2.5x10 (or 2-56) screws X 5
               M2.5x6-8 (or 2-56) screw X1 (This screw goes in the top hole near the IO ports and is just for looks)
• Pi - M2.5x6-8 (or 2-56) screws X4