Interesting bit of news. Previously it seemed impossible to order just a v6 gearbox shell from classic army.
Well since I've gotten no love from any vendor, I reached out again to the CA corporate site and again reiterated my situation that I would like a spare shell. (among other parts not listed on any vendor site)
They forwarded my request to their flagship store who have put one on order for me. The cost is 45$ for the shell and motor cage plus shipping. I'm currently waiting for it to become available to ship.
So that means if anyone needs a shell they don't have to use the shitty misaligning KS one or the weird bushing TM version that sometimes doesn't like v2/3 gearsets.
contact info for the classic army shop is
mkshop@classicarmy.com