The ability to make our own carpets

You kinda can. In the block dimeinsons setting for custom block you can change the min and max x,y,and z variables.

• Lower half slabs would have the settings: 0, 0, 0, 1, 0.5, 1 (min x, y, z, max x, y, z)
• Maybe for carpets try: 0, 0, 0, 1, 0.1, 1. This would be 1/5th the height of a slab

My 2.0 ideas include instant block models, So it can include that too! :D