I would love to have something like this as a block: http://www.schornsteinmarkt.de/images/product_images/original_images/2016_0.jpg
It would be awesome if you want to build Farms or something, using it as roof for a Storage Silo thing.

Oh goody, circles in minecraft!

I don't mind simple shapes, but that is way beyond this mod. You'd have better luck implementing it using models, and another mod.