I have two Light Raiders, one Raider and one Salvage Cruiser from a Mongoose Publishing box set with some Klingons. So these are about 1:2500 scale and are very nicely detailed. Amarillo Design Bureau still produce these and you can get them at their web store.
I don't want a large fleet of these guys, as Orion's tend to run around in small groups of ships. Cartels will either pilot their own ships or lease an operating space to other pirates, taking a percentage of the profits. The Salvage Cruiser will often act as a mobile base, refuelling and reloading raiders and also storing their ill gotten gains.
The second most common Orion ship found throughout the quadrant is the Orion Raider. A small, highly manoeuvrable light cruiser capable of going toe to toe with most Escorts and Frigates.
I'm tempted to get one or too more from Amarillo Design Bureau but these four make up a good little pirate raiding fleet able to harass my ACTA Star Fleet cargo vessels. I think the colour scheme works out well also.