Tiny Craft Mod Project MODDER NEEDED

Hello, here is one of the many mods I have in mind. Tiny Craft! This mod would allow you to change your size in the menu, NOT THE SIZE OF THE WORLD! There would be Normal size and 1:8 size (8 times smaller). This mod would fit with Little Blocks Block mod. But Tiny Craft by itself would be epic. Imagine yourself running in a huge cavern, with a giant zombie running after you!

Optionnal (the following would be nice but not necessary):
-while tiny, you can run on water for a short period
-Able to walk under fences.
-jump 1 block high for the playability
-running speed /2 (should be 8 but that would be too slow)
-and any other ideas you guys will have

I am not a modder myself, thats why I am looking for help. Still I am ready to do anything to help