Yikes!
Well, whenever I have some time on my hands after I get Misheru's Makoto back on her feet I will have to get some of the plastic components shown. I know Parabox sells them. The most difficult part appears to be fabricating the limb and neck attach points.
I must admit, I prefer the engineering in the Obitsu frames. The 50cm chest piece is a marvelous example of solid and yet flexible design, even the Obitsu neck pieces (with all their flaws, are a more simple design, and more solidly made than the ones I've seen from Volks. We got an aluminum replacement piece for a Volks neckpiece, and it's more like the Obitsu design using a captured ball joint. Actually the Volks replacement part uses two captured ball joints to allow a high degree of movement. It's vastly superior to the somewhat fragile Volks part, and doesn't use a spring that looks like it would be at home inside a cheap ball point pen - unlike the flimsy Volks one.
I have to admit though, the neck piece design that Obitsu uses right now, causes issues with eyes in the smaller heads. There is entirely too much neck piece inside the head. It kinda seems a re-design might be in order...