They were built using a combination of Cadian and High Elf bits, with Bolters taken from various sources. The Missile Launcher is a Hunter-Killer Missile.
Here's a group shot:
There's still a lot of work to be done on these, but you can get an idea of what the finished unit will be like.
I quite like them, although they're turning out a lot darker than I want them to be. I might strip them down again later and experiment some more, but for now i'll wait and see how they look alongside my Scarab Occult units.