Make the rest of the pyramid out of the ground. That's a bit more impressive than glass, isn't it?
This and the above, making things go up is one thing but carving things out of natural ground allows more freedom. I like to carve upside down towers (with the entrance at the top of the tower) and excavate the rest of the world down. You could just mine each wall out and replace it with glass after your done, and dedicate whole floors to tree farms. You can also import wood when you run out, caravans bring anywhere from 10-90 logs depending on how many logs you have.
See, scouring off 34 z-levels, killing my ocean and eliminating all my sand & clay, would make this project a massive nightmare. Plus, the cavern layers 1 & 2 are less than 34 levels down, as is my main source of magma.
You can just get your current world's seed and increase the sky level for that, then regen it, I've done such a thing and the world gen doesn't change aside from height.
If this is true, then I lose a lot of work, but not the site itself. I can live with that.
(Edit: Any ideas for how to recapture that seed number if it isn't visible in the advanced worldgen pane anymore?)
(Edit 2: Found it. It's in gamelog.txt.)
So digging into site-##.dat is daunting with no experience at reverse engineering file formats. It seems to be 100% binary, with no easy to parse text. That surprises me; I guess unit data, like names and nicknames, is held elsewhere. So far, I'm looking for large uniform areas of data to represent the existing 16 sky levels, reasoning that as empty space, they should be relatively uniform. Unfortunately, no such luck. For all I know z-levels aren't grouped together; it might be groups by x-planes or y-planes. Or some other, alien, voxel-like schema.
OTOH, I just found where my various uninvited guests are saved in "world.sav" and what their poisons do. Turns out I've got a pretty care-bear world -- only one creature is made of tough materials (chromite), and only one has a necrotic poison. The rest are all flesh and weak materials with poisons that do no long-term damage. This makes me want to keep the world even more...
I think I'm going to test the seed + extra z-levels idea. Reading the local region data is so far an exercise in futility.