I never even went that far. I'm cheap, for a cnc run I would want the design to sell for abour the hundred pounds mark, I'd hope for it to be something fairly simple, but to be popular it would need to be 18350 to 18650 kick compatible, personally I like telescopics over modular, bits lying about bother my ocd, but what I would really want to do is single tube, magnetic switch, m20x1mm threading, and as low a volt drop as possible.
I do intend to turn a mod purely for myself, I have some odd sized cells and I'd like to get one in a mod, they have a continuous draw limit of 60 amps....