There was a Darkstar at Castle? And I missed it!
The name escapes me now.... Section 8 paintball, perhaps? I have no idea how many were made, but styles varied. They did conversions and sold new ones. My favorite (neatest) was the Nova 700 conversion. They used the back of the tube as the reg housing and a MASSIVE piston actually moved within it. Only saw one that style (of course I've only ever seen ~5 Darkstars, most I worked on but were not mine). Mine is external reg SN style.
Another neat addition was a spring loaded detent in the breach to prevent double feeding.
No, it will take more than a kidney to get mine :-) I had to sell my ET to get it.