Like biomes but different

How would I go about creating a byte (or any piece of data) of storage per column on the y coordinate (like a biome)?

I cannot simply add biomes of different types because say I need 3 bits of extra information, I would require 8 times the amount of biomes to add this. Given that minecraft already has 78ish biomes to start with, doing this is a bad idea.

Could I replace bedrock with a custom block that stores this information (The storage gained from metadata would be enough for my purposes) or would this be the wrong approach?

Or in general, how do I add more non-block data to the world per column?