The Leviathan Crusader is now mostly assembled, and I was able to get it base coated last night. I gave up on having dozens of sub-assemblies and have assembled most of it, it just means that there will be a few fiddly bits when doing the fine detail work.
Photos of the model on its own don't generally do it justice: this thing is big. Here you can see how the legs compare to a normal AoBR Marine:
And a Land Raider: