For my kroot beasts I used a normal minotaur with a Krootox head
You might be able to do something similar, just instead of the mino head you use something more snakelike?
Or, if you want to go for the slithery look, maybe you can use a tyranid ravener's body, and use gor arms and do a conversion for the weapons.
Only problem now is you can't do biz orders for little things like heads unless you can find another line that would let you do it with something more compatible
One other thing you could try is
Crocodile games.. they have an ancient egypt themed game with a crocodile army that might make for some interesting "minotaur" conversions. I've ordered a few different figs from them for my tomb kings army. I'm hoping they put out a bone giant that doesn't have a monkey head some day...