When in doubt, Crute it out. When you want a real ripper that can sway the tide of battle.
I remixed a couple parts to be used in a fashion as shown in the photo.
The rest of the robot parts are here: https://www.thingiverse.com/thing:3021314
The saber tooth skull is here: https://www.thingiverse.com/thing:472463
EDIT 10/15/19: Corrected link for roboty parts.
You will need official heads to complete these models. I recommend purchasing the box sets for those. Hopefully this will tell THEM that we want more options to add them to our armies.
If you feel the overwhelming inclination to show your gratitude, tips are always greatly appreciated.