Battlefleet Gothic: Remastered includes rules for the Ramilies Class Star Fort, which can be used as an orbital defence or as a replacement for a planet in some scenarios, and for fortress-monasteries, which can be taken in Space Marine crusade fleets.
This 3D-printed proxy will work nicely as a Ramilies or as Aegida, the fortress-monastery of the Scythes of the Emperor.
More pictures below the fold.
