Ok, so while I'm pondering the question of the colour scheme, I've been building some pre-heresy marines. Although I don't have the book yet, I've been basing them off what I know about the new book, based off my gleanings from the internet.
Here's my Legio Praetor, Garus Morkaddon. As you can see, I've been quite conservative with his armament, sticking with a power sword and bolter. Chances are he'll have access to powerful and exotic weaponry, but there's no point jumping the gun. If I come across a must-have combo for a Praetor later, he can always be re-tasked as a squad leader
Next up is a basic Legionnaire with a bolter. I've given him a bolt pistol too, as apparently they carry them as sidearms. Like I said, nothing special, more of a test than anything.
And going back to my older pre-heresy project, here's one of my Thousand Sons, very nearly done. I just need to do his helmet crest and armour cabling and he's ready to go.
He's made it into this post mainly because I'm planning to re-visit my old plan for fielding my Pre-Heresy Thousand Sons (at least till the Prospero book arrives), by using them as Seeker squads - the Legio version of Sternguard Veterans
Plus it's nice to show I'm actually making progress now and then