Well, I ordered some Grey Knight torsos and built the first three of my MKVIII marines using some Secret Weapon Urban Ruble bases. Right after finishing them I ran across this image and realized that the MKIV is way cooler than the MKVIII and that I would have to use it instead, especially the ones that don't have the cables on front.
So, looking at the forgeworld site I realized that there are a couple of Heresy sets that contain these torsos:
I settled for the first two, the Recon will have to wait until I get around to another squad, and I also ordered the Red Scorpions Upgrade Pack. I will use the helmets, the sergeant torso and the pads from it together with the torsos and the legs from the other two sets. I will also add the arms and bolters from the new plastic tactical squad. This will probably be the most expensive squad that I have ever build, only the Forgeworld stuff set me back £94.30 and then I haven't bought the tactical squad yet, but on the other hand I think they will look stunning and that will motivate me to paint them to the highest standard. Now I just have to decide if the sergeants will have their helmets on or not.