Here's something I've started knocking together. I know he's not a Son of Horus, but I want to test out a Primus Medicae in my next game and I figured that if I'm going to field a Chief Apothecary, I might as well use Fabius
I did some minor conversions to him, namely filing down his overly-chaotic shoulder pads. His right one needs replacing at some point, as the filing has left it lopsided, but he'll do for now. I'll probably end up converting some allied Emperors Children to accompany him at some point.