A long time ago, I purchased a box of necrons with the explicit purpose of using the parts for conversion work. Although my conversions with them have been limited (see: 1, 2), I did end up assembling a whole squad (or perhaps killteam) of them and painted them up in Verdus Prime colours.
The idea for Verdus Prime originally came from the Dawn of War computer game wherein that faction of necrons appealed to me due to their colours and ease of identification on the battlefield. I still like the colour scheme, but painting white still holds problems for many people; including myself. I recently had a go at doing white properly for a long-barrelled marine miniature and was happy with the outcome. But for the necron, the white is pretty solid and makes for a stark contrast with the darker, silvered parts. Moreover, the oily streaks that I've added to all of these Verdus Prime necrons accentuates and, indeed, feeds off the sharp white colour of the necron's colours. For the eyes, I tried to use blood red to give them a grim-determination terminator style look. In a number of my images, this feature is lost as the colour gets washed out by the brilliance of the white in the colour balance. The necron symbol / rune in the centre of the chest is picked out with a goblin green colour.
For the Gauss barrel, I wanted for something a little more original than gluing the green plastic in to place. So, I painted dark green in erratic strokes along its length to give the impression of energy coursing through it and ready to erupt at the terminal end. Since the barrel is transparent, it is easy to see the strokes on the opposite side and therefore the adage of "less is more" applied to this process. Moreover, the barrel has the benefit of looking different depending on the angle that the observer views it from -- this aspect appealed to me greatly in the final result.
But should I turn my small killteam of necrons in to a full-blown army now that the new codex: necrons have come out? Hmmmmmmm.