Adding to the growing squad of melta gunners for my 30k army is this space marine - toting both a melta-gun and lobbing a grenade with the left hand. Again, this army is going to follow the maxim of mo model unconverted, as well as trying to make as many models true scale (regardless of terminator legs) as possible (before it kills me).
The head of the marine is taken from the chaos space marines range -- it is the Nurgle head with the chaotic extensions removed and filed down to a smooth finish on the left hand side of the image. Indeed, with the head turned to look at where the grenade is being lobbed, the scrubbing away of the gribbly Nurgle bits can hardly be seen.
The legs are from the regular space marine range, extended a few mm's to something more resembling true scale, and greenstuff at the hips added to the leg extensions. In hindsight, I think green stuffing the knee regions is easier for this kind of conversion, unless one is really wanting to change the angle the hips make with the thighs.
The torso and arms are from the chaos space marine range. There are plenty of bits from this range which work very well for 30k armies, but you'll notice here that I've shaved off the belt buckle. I'll paint over this with a legion symbol (or at the very minimum a Greek letter) when I'm at that stage. The back pack is from the grey knights range and to represent a marine that might be able to deep strike in to play.