Here's the OC I've been working on for a while. I DID NOT sculpt:
Gun (aside from the handle)
Joints + sockets
GI: Joe Straps (ankles and holster connection)

Everything else was sculpted using super sculpey/fixit sculpt. The figure is ridiculously small, standing about a 2 heads taller than your average GI:Joe/SW figure, and contains:
Triple ball jointed neck (two balls connecting to neck piece slide up and down, allowing for height adjustment), double jointed torso, and ball jointed inner shoulder joints (all of these are the less obvious points of articulation, not all of them). Holster and shield made out of styrene sheets.

Vague recipe:
All of the sockets are poly pieces from gundams/kotobukiya kits. The shoulders (not the inner ball joint) are ankles from a halo ODST figure, the ankles are ball joints from some older gundam, with polycaps from an old kotobukiya kit. The torso double ball joint is from the ODST's neck, the sockets from gundams. The shoulders are Reach wrists, the neck is a bunch of different sized sockets/ball joints, the knees are from a Joe, and the hips are the second to smallest Revoltech joints.