I've given up on finding a Ghost Ark that isn't either pre-owned/built or selling above MSRP on eBay. They've been consistently out of stock from GW for something like 9 months. As such, I've decided to take matters into my own hands and build something. The plan is to do a floaty pyramid with a "teleportation matrix" built in as a big lens and then something Canoptek looking to carry the weapon systems. I'll do something similar for the Doomsday Ark.
I threw together an initial Mk1. I think it needs some detail work, but overall I'm pretty happy. The pyramid base is about 60mm across, so it should be roughly the same size as the pilot's area on a real Ghost Ark.