My wife, however, was unwilling to play along with the project, so I used a mannequin bought from eBay as the base ;)
Step 1: Dismantling original PC
Step 2: Preparing the Mannequin
Using a small hacksaw I cut around this seam, with the only issues being the steel mounting points that are meant to be used to secure the mannequin in shop displays. The mounting points in the left leg and neck aren't required, so are removed, and the hole left by the removal of the neck plate is filled to create a power button location.
The nipples that were on the original moulding were also unwanted, so were filed off, filled and sanded smooth.