I did a thread on my IG a while ago, they have an urban color scheme.
You can find the thread
here
But, that thread assumes you are using Cathacan models. At the time I had still not get any Cadian models for my army...(I wonder if they had been relelased?).
But as an addendum,
The Cadian Model Way to paint Urban Ig...PrOtOcoN style.
Steps 1-3 remain the same, finish the clothing before moving onto the armor.
Step 3 (II).
Since you undercoated the model black and the armor is black you won't need to do much at this stage except make sure all the armor surfaces are black and that it is thick enough (in case of a spray coat or thin coat). Highlight the armor edges with a light brush of codex grey followed later with some fortress grey. To clarify, by armor I mean: The models helmet, breastplate, backplate, shoulderpads, the reverse T at the back where the backplate meets the belt and for the purpose of following this guide you can count boots as being "armor" too since you'd pretty much paint them in the same way.
Step 4, 6 and 7 remain the same except for a small addition of the bayonet, which is simply painted boltgun metal over chaos black and highlighted with mithril silver.
Step 5. Extras.
A major change from the cathacan models. All pouches and holsters are painted codex grey, making sure the any openings, gaps and such have a chaos black border. There is no white "camo lines" on any of these. The small nub inside the extra lasgun cartridge is painted with a small plop of boltgun metal.
Step 8. Finishing touches.
Here there's a slight change if you are doing, for instance, a Sgt. model with a chainsword. The Sgts sleeve stripes are painted Shining Gold. Everything not mentioned here most likely follows the set theme of dark black/grey tones into extravagant gold to cold worn metal.
That's it, that's how I paint my Urban IG.
You can expect pictures around Monday, since I'll propably be able to steal a camera by then ^_^
Now, hope you enjoy and please and questions and comments, I'd be more than happy to answer.