Narrative campaign army - 500 points

Hey there!

I've been invited to take part in a narrative campaign at a friends place, and I'm planning on using his Dark Eldar for it.  The background is as follows...

Synopsis: Deep within the Orbissus Cluster lies the secret research laboratories of Shadow-Corps, a company with a mandate to create and develop technologies and bio-chemical agents to help defeat the enemies of the Imperium. Contact was lost with Horreum IX and a coded distress signal has revealed that dark powers have been unleashed upon the research laboratories. As players in this Campaign you will either control a Black Ops team charged with removing key technologies from the foundries and labs, or executing the now stark raving mad personnel still surviving the events on Horreum IX and now presenting a security risk to the Imperium, or you will be playing as an enemy of the Imperium, either taking advantage of the chaos to infiltrate and steal Imperial secrets, or assassinate important scientists who might otherwise prove useful to the Emperor.

Rules look like this...

This is the second Foundry Campaign for 40K and the idea is to bring in some of the less experienced players with a game that allows them to compete and at low cost because it is limited to 500 points. There will be no models above 2 wounds permitted and no vehicles ( be they tanks or fliers ) that cost more than 50 points to field. Force Organisation is 1 HQ, 2 Troop minimum.Clarification: Bikes, Jetbikes permitted ( each bike and jetbike is bound to be under the 50 points anyway but I was asked, and these are fine )

I know there are a couple of Dark Angels, Chaos Marines and Farsight Enclave signed up for it.  But I could use a hand in coming up with a list.  My first thought was Baron, a couple units of hellions and some reavers.  Then I started looking at hexrifles in the codex, but realised they weren't as good as I was hoping   

Any and all comments welcomed

I don't like the rules. It sort of penalizes armies that don't have super cheap vehicles/transports, and poor jump infantry. DE's options on jump infantry sucks, and our cheapest vehicle is 5 points over the maximum. This takes away DE's two biggest advantages: Firepower and Mobility. If you make DE slow and not have good long range weapons...nah. Not good.

DE sort of suck without their vehicles. The rules kind of screw you. But they're great for marines(can take rhinos/drop pods). Go figure.