Ofcourse you need a proper WYSIWYG model for each character so GW might just be trying to get everyone to have 10 different HQ units to build armies with. I have been trying to repurpose other models to make the characters.
Here is my Pedro. Nothing really special. Left over bits from a Space Marine Commander Kit who just needed a combimelta changed to a Storm Bolter and a Banner to represent the Inspiring Presence ability. I will probably base it with a ork skull I have in my bit box.
Here is the mini I will use for Sicarius. With the new costs for power weapons and plasma pistols, I just could not see the advantage to having 3 veterans with both. So 1 becomes Sicarius with the addition of the Halo. Another lost his power weapon for a chainsword.