This is a small (not so small now) project I've been working on. It changes the in-game GUI to better suit skyblock, for example: The GUI can be toggled on/off with [right ctrl] and the settings menu ...
java.lang.IllegalAccessError: tried to access field net.minecraft.client.renderer.entity.RendererLivingEntity.field_77045_g from class net.minecraft.client.renderer ...