I've had these guys for a couple of years now. At least the scout bodies. I couldn't figure out which heads to use.
After moving them up to my work desk and looking at them for months I decided to have a shuftie to see what would be the best thing to use to convert them to look appropriately Thousand Sons-y. And the thing that stood out the most was the heads for the Van Saar from Necromunda. I fortunately had a box of those guys lying around and voila!
I'll probably do more with the cloaks later. For now they are good enough for the table tomorrow and I stlll have to assemble and paint the other half of my Occult blades squad.
Bonus Sons of Horus moritat.