Nice pictures! I watched a documentary recently about how the Egyptians built pillars like the ones in your picture- by placing the first rock that would be the pillar's base, then piling dirt around the rock to use as a ramp to stack the next rock and so on. When they placed the top pillar rock, they slowly removed the dirt and carved the pillar sides into shape on the way down. And here I always thought they made their pillars with the same alien levitation ray that they used to build their pyramids 
You can convert most Objects into Items without a lot of effort. Items have their own limit (separate from Objects) so that helps some. I think Tom (who made Diadem of Maunstraut) just copied the contents of the "OBJ" folder into the "ITEM"- I don't think it ever caused any problems.
You can also divide your big maps into smaller linked maps, but that might take a bit of work if you're already underway.
You can convert most Objects into Items without a lot of effort. Items have their own limit (separate from Objects) so that helps some. I think Tom (who made Diadem of Maunstraut) just copied the contents of the "OBJ" folder into the "ITEM"- I don't think it ever caused any problems.
You can also divide your big maps into smaller linked maps, but that might take a bit of work if you're already underway.