Wuppy's tutorial stops short of actual rendering and modeling of mobs.
"Go check the source" is not a very helpful reply either IMHO, as Minecraft Vanilla mobs don't use proxy classes for rendeing, nor do they use any forge hooks.
I can find 50 tutorials on how to make a block, but 0 examples on how to create a mob.
I wouldn't even need a tutorial but, are there any public examples available?